Off by one fix for btrfs_drop_extents

One of my old patches introduces a new bug to
btrfs_drop_extents(changeset 275). Inline extents are not truncated
properly when "extent_end == end", it can trigger the BUG_ON at
file.c:600.  I hope I don't introduce new bug this time.

---
Signed-off-by: NChris Mason <chris.mason@oracle.com>

fs/btrfs/file.c

@@ -481,8 +481,9 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 			search_start = (extent_end + mask) & ~mask;
 		} else
 			search_start = extent_end;
-		if (end < extent_end && start > key.offset && found_inline) {
+		if (end <= extent_end && start >= key.offset && found_inline) {
 			*hint_byte = EXTENT_MAP_INLINE;
+			continue;
 		}
 		if (end < extent_end && end >= key.offset) {
 			if (found_extent) {