NFSD: Check status from nfsd4_map_bcts_dir()

Compiling gave me this warning:
fs/nfsd/nfs4state.c: In function ‘nfsd4_bind_conn_to_session’:
fs/nfsd/nfs4state.c:1623:9: warning: variable ‘status’ set but not used
[-Wunused-but-set-variable]

The local variable "status" was being set by nfsd4_map_bcts_dir() and
then ignored before calling nfsd4_new_conn().

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>