nfsd4: fix error return in non-matching-creds case
nfsd4: fix error return in non-matching-creds case

Note CLID_INUSE is for the case where two clients are trying to use the
same client-provided long-form client identifiers.  But what we're
looking at here is the server-returned shorthand client id--if those
clash there's a bug somewhere.

Fix the error return, pull the check out into common code, and do the
check unconditionally in all cases.

Signed-off-by: J. Bruce Fields <51738506c1b2ccb0761f23bdc612c93babf738ea@redhat.com>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas