Log Message:
-----------
Reduce unnecessary PANIC to ERROR, improve a couple of comments.
Modified Files:
--------------
pgsql/src/backend/access/transam:
xlog.c (r1.309 -> r1.310)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/xlog.c?r1=1.309&r2=1.310)