Fix parsing client_address RTS command in RPC/HTTP Proxy

See [MS-RPCH] section 2.2.3.5.12.

It was referencing to an invalid var name and renaming variables
to match what is actually storing.

Pair-Programmed-with: Javier Amor García <jamor@zentyal.com>
Merge pull request #159 from sixstone-qq/ejhernandez/fix-client-address-cmd-RTS-PDU-OA

Fix parsing client_address RTS command in RPC/HTTP Proxy