allow cinder to connect to mysql from compute

and other services as well otherwise it fails during startup.

Signed-off-by: Loic Dachary <loic@dachary.org>
Merge pull request #130 from dachary/wip-cinder

allow cinder to connect to mysql from compute
Merge pull request #131 from michaeltchapman/from_dan

Dev
Add installer branch support