Add missing tests for provider_fw_rule_* methods

There was no tests in test_db_api for provider_fw_rule_*
methods.

Add tests to ensure that all works.

blueprint db-api-tests

Change-Id: Ia137ffcfcba3f663a177386775147a25d6716980
Merge "Add missing tests for provider_fw_rule_* methods"
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp