libafs: revert init req to use the real uid

libafs: revert init req to use the real uid

The commit to use wrappers for creditial structure access
inadvertently changed the user id to be the effective uid instead of
the real uid, when no PAG is present, on linux.  Revert this so
setuid programs continue to work.

See commit eb8e55bba7740a87e07ef07bb4b789e6d4e36f0d

Change-Id: I5d42b8caf90a042192ed39f26e55d70c9531f2e9
Reviewed-on: http://gerrit.openafs.org/7931
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit 1a1e87dcdf972519cd21970f7c78709e40f8e1e9)
Reviewed-on: http://gerrit.openafs.org/7990