Btrfs: fix error handling in btrfs_ioctl_send()

fget() returns NULL if error. So, we should check NULL or not.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

fs/btrfs/send.c

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 158b919..2037fc0 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -4612,8 +4612,8 @@
 	sctx->flags = arg->flags;
 
 	sctx->send_filp = fget(arg->send_fd);
-	if (IS_ERR(sctx->send_filp)) {
-		ret = PTR_ERR(sctx->send_filp);
+	if (!sctx->send_filp) {
+		ret = -EBADF;
 		goto out;
 	}