Catch glance image create exceptions

Catch exception from glance when image creation fails because the
requested name is too long. Currently the exception is not caught
in the api which results in an 400 Bad Request correctly being
returned, but also leaving a traceback in the logs. Correctly catching
the exception and explicitly raising an HTTPBadRequest removes
the production of the traceback.

Fixes bug #1169560

Change-Id: I511da79cb0b1b4578bf43f0819b2ac64fb6e5fb3
(cherry picked from commit 09c7fc3b694ab401d42c9e59b17e24bbe4383588)
Merge "Catch glance image create exceptions" into stable/grizzly