ModifyVolume attributes on Clone.

Clones copy over the attributes from the source volume,
we want to keep some admin data like source-volid and if
it's a clone or not.  To do that we just need to call modifyvolume
after the clone operation and update this info.

Change-Id: I903fe6f8a57880abad8d315d091c1e57624a519c
Hack run_tests.sh to work with single tests again.

Even though we're moving to testr and this will eventually
go away, we should maintain our ability to run and debug
individual tests until the broader change is released.

This just adds some text around the nosetests call
to get us back where we were.

Fixes bug: 1181996

Change-Id: Id0082ca8954664679430cc602425b1fadd29151b
Merge "ModifyVolume attributes on Clone."