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)