Configure for stable/grizzly

Set default TARGET_DEVSTACK_BRANCH to stable/grizzly

Change-Id: I53d5603bac55f400fc5b3fe6a9c59d7c9cce9ebc
set cannonical upstream url to openstack-dev

Change-Id: Id5f292205cf4fe7dfa20d218aa31f6f43c49cc86
Merge "set cannonical upstream url to openstack-dev"