Clean partial downloads from cache

When using "pacman -Sc" to clean the cache, it make sense to also remove
partially downloaded files.

Fixes FS#34317.

Signed-off-by: Allan McRae <allan@archlinux.org>

src/pacman/sync.c

@@ -238,9 +238,7 @@ static int sync_cleancache(int level)
 					/* skip source packages within the cache directory */
 					"*.src.tar.*",
 					/* skip package deltas, we aren't smart enough to clean these yet */
-					"*.delta",
-					/* skip any partial downloads */
-					"*.part"
+					"*.delta"
 				};
 				size_t j;