fix build

inode_allocate_file_extents should return NULL if allocation fails.

Bug: 16984795
Change-Id: I7d2b9d61ca81f8e1869dbac3d8bde79bb5799fa9
diff --git a/ext4_utils/extent.c b/ext4_utils/extent.c
index 7142c8b..1900b10 100644
--- a/ext4_utils/extent.c
+++ b/ext4_utils/extent.c
@@ -210,11 +210,11 @@
 	alloc = do_inode_allocate_extents(inode, len);
 	if (alloc == NULL) {
 		error("failed to allocate extents for %"PRIu64" bytes", len);
-		return;
+		return NULL;
 	}
 
 	extent_create_backing_file(alloc, len, filename);
-    return alloc;
+	return alloc;
 }
 
 /* Allocates enough blocks to hold len bytes and connects them to an inode */