nfsd41: modify the members value of nfsd4_op_flags

The members of nfsd4_op_flags, (ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS)
equals to  ALLOWED_AS_FIRST_OP, maybe that's not what we want.

OP_PUTROOTFH with op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,
can't appears as the first operation with out SEQUENCE ops.

This patch modify the wrong value of ALLOWED_WITHOUT_FH etc which
was introduced by f9bb94c4.

Cc: stable@kernel.org
Reviewed-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>