side fails, the entry in the cache is left with no valid context
(gd_ctx == GSS_C_NO_CONTEXT). As such, subsequent hits on the cache
will result in persistent authentication failure, even after the user has
done a kinit or similar and acquired a new valid TGT. This patch adds a test
for that case upon a cache hit and calls rpc_gss_init() to make another
attempt at getting valid credentials. It also moves the setting of gc_proc
to before the import of the principal name to ensure that, if that case
fails, it will be detected as a failure after going to "out:".
Reviewed by: dfr
Approved by: kib (mentor)
b211588596