Deleted Bootcamp partition and it just disappeared. Nothing to merge with OSX partition
You show in your posted image that the partition is encrypted. I was unaware a partition could be encrypted without using core storage. Anyway, I believe the correct command to fix your drive is given below.

sudo  diskutil  resizevolume  /dev/disk0s2  R


The command should move /dev/disk0s3 to the bottom of disk0 while resizing /dev/disk0s2 to maximum size. I am not sure if the sudo prefix is required.