Make running of unit tests more robust

Unit tests would fail if run from a symlinked directory.
To fix this, this patch adds the -P switch to the pwd command,
to make sure all files are referred to by their actual paths
and not symlinks.

Change-Id: Ib7087c11f9dc2c44be3aca8cf94db227a2db72f3
Closes-Bug: #1266220
Allowing snapshoting attached volume

The cinder api allows calling snapshot on attached volumes,
we should enable it on horizon.

Change-Id: I33d7bbca0bf993ace7c243867aa5f57438a57a5d
Fixes: bug #1202929
Merge "Make running of unit tests more robust"
Merge "Allowing snapshoting attached volume"