Updating HACKING file

Using OpenStack HACKING file for common stuff and mentioning locals()
disallowed now like Cinder.

Change-Id: I05b1706eb52c13b9eb89fe5cbcce005c3cc75caf
Add evaluation of --force parameter when creating snapshots

Raise BadRequest Exception if value of --force parameter in
snapshot-create is invalid

Fixes: bug #1014689

Change-Id: If4858dc17cedf027112defb935016137727681cc
Merge "Add evaluation of --force parameter when creating snapshots"
Merge "Updating HACKING file"