pgsql: Remove Jan Wieck's name from copyrights, and put in standard

Log Message:
-----------
Remove Jan Wieck's name from copyrights, and put in standard
boilerplate, with approval of author.

Modified Files:
--------------
    pgsql/src/pl/plpgsql/src:
        gram.y (r1.86 -> r1.87)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/gram.y.diff?r1=1.86&r2=1.87)
        pl_comp.c (r1.99 -> r1.100)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_comp.c.diff?r1=1.99&r2=1.100)
        pl_exec.c (r1.161 -> r1.162)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_exec.c.diff?r1=1.161&r2=1.162)
        pl_funcs.c (r1.47 -> r1.48)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_funcs.c.diff?r1=1.47&r2=1.48)
        pl_handler.c (r1.27 -> r1.28)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_handler.c.diff?r1=1.27&r2=1.28)
        plpgsql.h (r1.68 -> r1.69)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/plpgsql.h.diff?r1=1.68&r2=1.69)
        scan.l (r1.44 -> r1.45)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/scan.l.diff?r1=1.44&r2=1.45)