fontsrv: disable X11 hinting

Discussion at:
https://groups.google.com/d/topic/plan9port-dev/L7RVkXPmrdY/discussion
https://github.com/9fans/plan9port/pull/7

Change-Id: I4f3a6791436120388ad8798e519f5e8473dd9306
Reviewed-on: https://plan9port-review.googlesource.com/1095