pgsql: Remove ancient PL/pgsql line numbering hack.

Log Message:
-----------
Remove ancient PL/pgsql line numbering hack.

While this hack arguably has some benefit in terms of making PL/pgsql's
line numbering match the programmer's expectations, it also makes
PL/pgsql inconsistent with the remaining PLs, making it difficult for
clients to reliably determine where the error actually is. On balance,
it seems better to be consistent.

Pavel Stehule

Modified Files:
--------------
pgsql/src/pl/plpgsql/src:
pl_scanner.c (r1.5 -> r1.6)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_scanner.c?r1=1.5&r2=1.6)
pgsql/src/test/regress/expected:
domain.out (r1.45 -> r1.46)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/domain.out?r1=1.45&r2=1.46)
guc.out (r1.10 -> r1.11)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/guc.out?r1=1.10&r2=1.11)
plancache.out (r1.9 -> r1.10)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/plancache.out?r1=1.9&r2=1.10)
plpgsql.out (r1.85 -> r1.86)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/plpgsql.out?r1=1.85&r2=1.86)