COE CSIT : Support for patch test for changes in golang

COE CSIT currently uses ansible playbook to bring up the deployment for tests.

In https://github.com/opendaylight/integration-test/blob/master/csit/variables/coe/coe_play.yaml#L32 we can see that we always checkout the master repo to build golang binaries, for running CSIT. Because of this, when we do patch tests, changes in golang are not applied, and only java changes can really be tested through patch test. We should figure out a mechanism to inject the patch information to the playbook, to checkout the same for tests.