pgsql: Allow plpgsql function parameter names to be qualified with the

Log Message:
-----------
Allow plpgsql function parameter names to be qualified with the function's
name. With this patch, it is always possible for the user to qualify a
plpgsql variable name if needed to avoid ambiguity. While there is much more
work to be done in this area, this simple change removes one unnecessary
incompatibility with Oracle. Per discussion.

Modified Files:
--------------
pgsql/doc/src/sgml:
plpgsql.sgml (r1.114 -> r1.115)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/plpgsql.sgml.diff?r1=1.114&r2=1.115)
pgsql/src/pl/plpgsql/src:
gram.y (r1.103 -> r1.104)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/gram.y.diff?r1=1.103&r2=1.104)
pl_comp.c (r1.116 -> r1.117)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_comp.c.diff?r1=1.116&r2=1.117)
pl_funcs.c (r1.60 -> r1.61)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_funcs.c.diff?r1=1.60&r2=1.61)
plpgsql.h (r1.89 -> r1.90)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/plpgsql.h.diff?r1=1.89&r2=1.90)
pgsql/src/test/regress/expected:
plpgsql.out (r1.55 -> r1.56)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/plpgsql.out.diff?r1=1.55&r2=1.56)
pgsql/src/test/regress/sql:
plpgsql.sql (r1.47 -> r1.48)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/plpgsql.sql.diff?r1=1.47&r2=1.48)