Revert "gpsd: update from 2.95 to 3.10"

This update broke gpsd because the download url changed and trying to
get version 3.10 from the old url returns an error document with a
timestamp resulting in new hashes on every build.

And more importantly, gpsd 3.10 switched to the scons build system, so
even if the download url was correct it will fail to build until the
expression is updated.

This reverts commit 3f1c26b8257201dde5fda0e7381bcf4ad7422d09.