Custom ringtone not working on Nexus 4 since OTA Lollipop
On my Nexus 4, for ringtones snipped by Ringdroid the following worked:
Ringdroid saves to the following folders:
sdcard/media/audio/ringtones
sdcard/media/audio/notifications
sdcard/media/audio/alarms
I copy-and-deleted the ringtones from those locations to the following folders:
sdcard/Ringtones
sdcard/Notifications
sdcard/Alarms

This left duplicate entries in the Android settings and messaging settings.  To fix that I then cleared the Cache Partition from the recovery in the bootloader by the following directions:
https://support.t-mobile.com/docs/DOC-5994
Here's a short version:
Power off
All three hard keys for about 10 seconds to enter the bootloader menu
Uses arrow keys to select Recovery Mode and power to activate
Power and Volume Up (to actually get into recovery menu I guess?)
volume to "Wipe Cache Data" and hit power
Return to bootloader
Start

You can now set ringtones and they will actually work.