SOLARIS: Reset syscalls on mod_install failure

SOLARIS: Reset syscalls on mod_install failure

If our call to mod_install fails for any reason (for example, if the
afs entry is missing from /etc/name_to_sysnum), we may still have set
the sysent structures for setgroups and ioctl to point at libafs code.
So calls to those syscalls will cause a panic, since the code they
point to is no longer loaded.

To avoid this, just reset the sysent entries back to what they were if
we fail to load, just like we do when unloading the module.

Reviewed-on: http://gerrit.openafs.org/4685
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit ca425b7d49a2bf4c079aa38c0abf68596eca0b30)

Change-Id: Ifb2cd9848b5468c950b600052308370b7c8c2af9
Reviewed-on: http://gerrit.openafs.org/4687
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>