Modify Solaris Rx NetIfPoller to avoid Panic

Modify Solaris Rx NetIfPoller to avoid Panic

This patch changes the common error reporting type from CE_PANIC
to CE_WARN and adds appropriate cleanup processing so that we do not
leak resources if an error occurs.

LICENSE MIT
FIXES 124498

Reviewed-on: http://gerrit.openafs.org/97
Reviewed-by: Russ Allbery <rra@stanford.edu>
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit ccb3e316868f381831d9ddda530af83102f67697)

Change-Id: I8e289d256e5cbc3d3724cafe7114a77f0ddd900a
Reviewed-on: http://gerrit.openafs.org/878
Tested-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@dementia.org>