Imported Translations from Transifex

Change-Id: I3c8e6595c12a2dabd15eb811f7d3fd5611427c6c
Added RpcProxy class

This class is intended for easy and iterative migration from
oslo-incubator RPC implementation to oslo.messaging. It will adapt
oslo.messaging API to old oslo-rpc interfaces.

Migrated all affected classes to the new RpcProxy class.

blueprint oslo-messaging

Change-Id: I1563c13b470b61eebc982ee81efee47732943d48
Introduced transition RPC exception types

These exception types will ease transition from oslo-rpc to
oslo.messaging.

blueprint oslo-messaging

Change-Id: I48d214d676e863d7a60d78c49d2fa917d47c07d9
Merge "Imported Translations from Transifex"
Merge "Added RpcProxy class"
Merge "Introduced transition RPC exception types"