More clear message when detaching volume

When detaching a volume from instance, the warning message looks like:
You have selected "/dev/vdb on instance test". Please confirm your
selection. This action cannot be undone.
If we consider that not all user's will be familiar with linux they may
not understand that vda in this warning means boot disk.
So use "volume abc on instance test" like message instead of the origin
one.

Change-Id: If1f7a161dfbc71ed22d286c65520b1500fb3a729
Closes-bug: 1281679
Icehouse release notes

Change-Id: Ic3f22f15191828b77a6838f3e4b2a53420e9e0f3
Exception handling should not use exc.message

In looking at
https://review.openstack.org/#/c/77613/3/openstack_auth/backend.py , it
occurred to me that many other instances of e.message are likely lurking
throughout our code. And especially because Alex Gaynor decided to weigh
in, I think we have a somewhat authoritative view of how this should be
solved.

Change-Id: If00dd70de07ffd278d72c7d5cdf9b0021da4663a
Closes-Bug: 1319918
Updated from global requirements

Change-Id: I0cd06ebbc66ebdd563dc198460f7bd4c92392fad
Merge "Icehouse release notes"
Merge "Updated from global requirements"
Merge "More clear message when detaching volume"
Merge "Exception handling should not use exc.message"