q2c: Remove final untranslated strings from q2c.c.

q2c: Remove final untranslated strings from q2c.c.

The "restrictions" that could be specified in q2c put strings
in the output that needed to be translated but could not.  This
commit drops the feature and removes all of its prior users.
Some of the users required new validation code to be added, but
many of them in the SET command did not because the value was
not actually used anywhere.