Refactor security group rpc call

Refactor rpc call of 'security_group_rules_for_devices' into
'security_group_info_for_devices' to reduce the response
message size and server side processing time. Includes
agent-side auto detection of rpc version, and fall back
to the old one.

Change-Id: If19be8579ca734a899cdd673c919eee8165aaa0e
Implements: blueprint security-group-rules-for-devices-rpc-call-refactor
DocImpact
Co-Authored-By: Miguel Angel Ajo <mangelajo@redhat.com>
Revert "Cisco DFA ML2 Mechanism Driver"

This reverts commit 3680fd61c9a1cceaa011b4d0d37d235abf490c50.

The reverted patch incorrectly ties with Keystone and should have never been
approved since the approved version only partially addressed review concerns.

This revert also ensure migration timeline integrity.

Change-Id: If5fbdade72c762b21a477676ded816ce5be97ca5
Merge "Refactor security group rpc call"
Merge "Revert "Cisco DFA ML2 Mechanism Driver""