Clean up duplicate code in v2.image_data.py

glance/api/v2/image_data.py:ImageDataController.upload has two identical
"except exception.StorageFull as e" clauses. One should be removed.

Fixes bug #1256207

Change-Id: I42fc5126e493591045d09ffb9abbc4816e63ef60
Merge "Clean up duplicate code in v2.image_data.py"