reiserfs: fix "new_insert_key may be used uninitialized ..."

new_insert_key only makes any sense when it's associated with a
new_insert_ptr, which is initialized to NULL and changed to a
buffer_head when we also initialize new_insert_key. We can key off of
that to avoid the uninitialized warning.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Jeff Mahoney <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: Jan Kara <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/reiserfs/ibalance.c

···
 				       insert_ptr);
 	}
 
-	memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE);
 	insert_ptr[0] = new_insert_ptr;
+	if (new_insert_ptr)
+		memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE);
 
 	return order;
 }