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: Iac5a2a4379a386393a42803821b8645764067521
Reviewed-on: http://gerrit.openafs.org/4688
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>