The C-Ares "done" file should have a name beginning with cares-.

Fix a presumed copy-and-pasteo.

Change-Id: I6953bfb46741923507bb58b4e48a72d92313e07c
Reviewed-on: https://code.wireshark.org/review/5012
Reviewed-by: Guy Harris <guy@alum.mit.edu>
(cherry picked from commit d93bf88af02a5c9e52c06c1e86844c48b90f2b59)
Reviewed-on: https://code.wireshark.org/review/5013