Take out parenthesis around faq.txt rule so it works when automake
chooses Korn shell instead of Bourne shell.  It still works with the
Bourne shell in my testing.

Change-Id: I00bfed22fb0d9bb183637ea5fb111904b8536949
Reviewed-on: https://code.wireshark.org/review/5880
Reviewed-by: Stephen Fisher <sfisher@sdf.org>