Make sure that variable num_files_total_local is declared

This variable is declared in `if m:`. Of course if this codepath doesn't
run, the variable is not declared an Python doesn't like this kind of
surprise...

Signed-off-by: Arnaud Rebillout <arnaud.rebillout@collabora.com>

src/modules/unpackfs/main.py

@@ -103,6 +103,7 @@ def file_copy(source, dest, progress_cb):
     if not source.endswith("/"):
         source += "/"
 
+    num_files_total_local = 0
     num_files_copied = 0  # Gets updated through rsync output
 
     args = ['rsync', '-aHAXr']