Add tests for nova.db.api.security_group_rule_* methods.

blueprint db-api-tests

Change-Id: I20b63683da78bcb99e1f88cc10ca71a64f1f17a9
Merge "Add tests for nova.db.api.security_group_rule_* methods."
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp