aufs: for v5.1-rc1, follow the new flag for current->atomic_flags

In mainline, by the commit
	71368af9027f 2019-01-29 x86/speculation: Add PR_SPEC_DISABLE_NOEXEC
a new flag is introduced.  And aufs simply follows it.
Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>

fs/aufs/super.h

@@ -425,7 +425,7 @@ static inline void dbgaufs_si_null(struct au_sbinfo *sbinfo)
 
 /* current->atomic_flags */
 /* this value should never corrupt the ones defined in linux/sched.h */
-#define PFA_AUFS	7
+#define PFA_AUFS	0x10
 
 TASK_PFA_TEST(AUFS, test_aufs)	/* task_test_aufs */
 TASK_PFA_SET(AUFS, aufs)	/* task_set_aufs */