ext4: remove useless s_dirt assignment

Clean-up ext4 a tiny bit by removing useless s_dirt assignment in
'ext4_fill_super()' because a bit later we anyway call
'ext4_setup_super()' which writes the superblock to the media
unconditionally.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/super.c

@@ -3277,7 +3277,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 #else
 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
 #endif
-		sb->s_dirt = 1;
 	}
 
 	/* Handle clustersize */