pgsql: Revert addition of units to GUC descriptions; doesn't affect

Log Message:
-----------
Revert addition of units to GUC descriptions; doesn't affect
postgresql.conf.

Modified Files:
--------------
pgsql/src/backend/utils/misc:
guc.c (r1.501 -> r1.502)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc.c?r1=1.501&r2=1.502)