Error message in create vol with a vol source

Updating the error message in the create volume form
for the case where the volume source is another volume
and the current volume size is less than the volume source

Change-Id: I53d5e9ffdea4344bafcaf3e0623e2e39c4c259be
Closes-Bug: #1291244
Merge "Error message in create vol with a vol source"