Prevent create volume from snapshot with bad size

Prevent to create a volume from a snapshot with a volume size less
than the snapshot size.

Check if a volume size is specified that it is less than
the snapshot size.

Raise a exception if it's lesser.

Fixes bug 1161841

Change-Id: Ic1afbfb025ce0b3906c35c6c50a71734d74a9851
Merge "Prevent create volume from snapshot with bad size"