pgsql: Fix some translator comments so that xgettext finds them and

Log Message:
-----------
Fix some translator comments so that xgettext finds them and pgindent does
not destroy them. Maybe we can adjust pgindent sometime.

Modified Files:
--------------
pgsql/src/backend/parser:
parse_clause.c (r1.158 -> r1.159)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_clause.c.diff?r1=1.158&r2=1.159)
parse_coerce.c (r2.145 -> r2.146)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_coerce.c.diff?r1=2.145&r2=2.146)
pgsql/src/backend/postmaster:
postmaster.c (r1.503 -> r1.504)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/postmaster.c.diff?r1=1.503&r2=1.504)
pgsql/src/backend/utils/error:
elog.c (r1.177 -> r1.178)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/error/elog.c.diff?r1=1.177&r2=1.178)