Can't delete partitions after attempting BOOTCAMP on my iMac 5k
Something went totally wrong and your Logical Volume Group is fragmented. You have to rebuild your Fusion Drive from scratch:

Preparation:


Backup "Macintosh HD" to an external drive with Time Machine
Detach any external drive (especially your external Time Machine backup drive)
Restart to Internet Recovery Mode by pressing alt cmd R at startup.
The prerequisites are the latest firmware update installed, either ethernet or WLAN (WPA/WPA2) and a router with DHCP activated.
On a 50 Mbps-line it takes about 5 min (presenting a small animated globe) to boot into a recovery netboot image which usually is loaded from an apple/akamai server.

I recommend ethernet because it's more reliable. If you are restricted to WIFI and the boot process fails, just restart your Mac until you succeed booting.

Alternatively you may start from a bootable installer thumb drive (Yosemite) or a thumb drive containing a full system (Yosemite).


Rebuild Fusion Drive  


Booted to Internet Recovery Mode open Utilities → Terminal in the menubar and enter:
diskutil cs list to get the CoreStorage listing.  
Copy the second Logical Volume Group UUID, it's the seventh listed in the listing of diskutil cs list.  
Then delete the second Logical Volume Group with diskutil cs delete LVG2UUID.
In your case: diskutil cs delete E0E4516A-DE3A-4B62-BE6A-855A760F5E3E
Copy the Logical Volume UUID it's the sixth UUID listed
delete the Logical Volume with diskutil cs deleteVolume LVUUID.
In your case: diskutil cs deleteVolume 00CDC215-F00D-4AD4-BA78-A2B220278688
Copy the first Logical Volume Group UUID, it's the first listed in the listing of diskutil cs list.  
Then delete the first Logical Volume Group with diskutil cs delete LVGUUID.
In your case: diskutil cs delete 8FCBCB92-43CC-45A2-A058-58CAF79B93B4
Enter exit and quit 'Terminal'
Open 'Disk Utility'. Enter 'Ignore' if you are asked to fix the drives.
Choose your SSD and partition it: 1 Partition Mac OS X Extended (Journaled),
hit the Options button and choose GUID Partiton table and hit OK and Apply.
Please check that the size is ~121 GB  

Example:
Beware! Since I took the screenshots in a virtual machine which couldn't be booted to Internet Recovery Mode i had to create two example disks with different disk identifiers and sizes. So don't use my UUIDs and disk identifiers recreating your Fusion Drive.


Choose your HDD and partition it: 1 Partition Mac OS X Extended (Journaled),
hit the Options button and choose GUID Partiton table and hit OK and Apply.
Please check that the size is ~3 TB  

Example:  


Quit Disk Utility and open Terminal
Enter diskutil list

Example (your disk identifiers and sizes are different of course: Your volume SSD probably has the Identifier disk0s2 and the size 121 GB and your volume HDD probably has the Identifier disk1s2 and the size 3.0 TB):


Enter diskutil cs create "Name" IdentifierSSD IdentifierHDD
In your case probably diskutil cs create "Macintosh HD" disk0s2 disk1s2.  

Copy the resulting LVGUUID

Example: 


Enter diskutil cs CreateVolume LVGUUID jhfs+ "Macintosh HD" 100%.

Example:


Enter diskutil cs list
Check the size of your Logical Volume. It should have the size ~3.121 TB

Example:


Quit Terminal
Open 'Disk Utility' and check your newly created volume for errors
Quit 'Disk Utility'


Restoring "Macintosh HD" from Time Machine backup (alternatively you may reinstall OS X and migrate your users and apps - see below)


Attach your external Time Machine backup drive or check this answer if you use NAS or another network share.
Open 'Restore from Time Machine Backup'


Choose the appropriate Time Machine backup and restore your system
The messages on your screen may differ slightly (different names and backup source)





Reboot to your restored system.
Unmount and detach your Time Machine backup drive
Open 'Terminal' and enter 'diskutil list'
Check if your 'Recovery HD' is listed.
If your 'Recovery HD' is missing, usually reinstalling your current system with the latest available system installer (e.g. 'Install OS X Yosemite (10.10.2)' if Yosemite is currently installed) will recreate it without loosing any data. AFAIK Recovery Partition Creator 3.8 will NOT create a Recovery HD on CoreStorage volumes.
After reinstalling the system with the latest available system installer open App Store and install the latest security fixes.


Reinstalling Yosemite from scratch and migrating apps &amp; data from Time Machine backup


Choose "Reinstall OS X"


Choose "Macintosh HD" as destination disk
after the download, installation and a restart the Setup Assistant will ask you - beyond other questions - to migrate users, apps and other data
attach your Time Machine Backup drive and wait a few seconds
choose "Migrate from Time Machine backup" (or something similar - i don't remember the precise message.)
finish the migration
start App Store.app and install the latest updates.