CA failure when system runs low on mbufs

The functions getpeername() and getsockname() were not
expected to fail if given valid arguments. The ca client
library assert failed when failure status was retuned.
The ca server library didnt clean up properly (crashed)
when failure status was returned. Unfortunately, in low
network buffer situations both calls have been recently
observed to return failure status.

Additional information:
The bug probably exists in all previous versions of EPICS.

Original Mantis Bug: mantis-34
    http://www.aps.anl.gov/epics/mantis/view_bug_page.php?f_id=34