Fix L2 agent does not remove unused ipset set

The patch fixes L2 agent does not remove unused ipset set when security
group contains rules for only IPv4 or IPv6.

Change-Id: I375b1683cd763c0a33dc935558c637874d36ffa1
Closes-bug: #1373287
enable F812 check for flake8

The change removes the shadowed variable in list comprehensions and
enables the F812 check

Change-Id: If7b4d6f198795565fe0d8e7524b73555e310cd14
Partial-Bug: 1329017
Drop usage of RpcProxy from DhcpPluginApi

Drop the usage of the RpcProxy compatibility class from the
DhcpPluginApi RPC client class.  The implementation has been updated
to use the appropariate APIs from oslo.messaging directly.

Part of blueprint drop-rpc-compat.

Change-Id: I81bfd761707c4c587b12877668c4399efe3d652e
Fix client side versions in dhcp rpc API

The dhcp rpc API has two version (1.0 and 1.1).  The proper way to use
versioning for this is to only specify '1.1' from the client side when
you require that the remote side implements at least version '1.1' for
the method to work.  Otherwise, '1.0' should still be specified.  The
previous code specified '1.1' always.

Related to blueprint drop-rpc-compat.

Change-Id: I9468f8f67d80c5d064137f917fc04f9335a3ed55
Merge "Fix L2 agent does not remove unused ipset set"
Merge "enable F812 check for flake8"