snapshot GC fix

tunasync_snapshot_gc.py

@@ -9,7 +9,7 @@ import toml
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(prog="tunasync_snapshot_gc")
     parser.add_argument("--max-level", type=int, default=1, help="max walk level to find garbage snapshots")
-    parser.add_argument("--pattern", default=r"^_gc_\d+", help="pattern to match garbage snapshots")
+    parser.add_argument("--pattern", default=r"^_gc_.+_\d+", help="pattern to match garbage snapshots")
     parser.add_argument("-c", "--config", help="tunasync config file")
 
     args = parser.parse_args()
@@ -27,7 +27,7 @@ if __name__ == "__main__":
                     print("GC: {}".format(abs_fname))
                     try:
                         sh.btrfs("subvolume", "delete", abs_fname)
-                    except sh.ErrorReturnCode, e:
+                    except sh.ErrorReturnCode as e:
                         print("Error: {}".format(e.stderr))
                 else:
                     walk(abs_fname, level+1)