Populate local address for rendezvous transporter.

[alex.burlyga.ietf_gmail.com]

Summary

When accepting a connection on underlying tcp socket rpc vc transporter fails to populate local address.
This change rectifies this problem by modifying rendezvous_request() to fill out the xptr structure member with appropriate information.

Test Plan

Verified existing mountd/rpc.statd are not impacted: cthon tests pass, mountd's procs still serve FHs, export lists, and mount list.
For testing the code, changed mountd to print local address under debug, verified expected result were printed.

[stas]

Looks good to me.