pgsql: Move plpgsql DEBUG from DEBUG2 to DEBUG1 because it is a

Log Message:
-----------
Move plpgsql DEBUG from DEBUG2 to DEBUG1 because it is a user-requested
DEBUG.

Modified Files:
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pgsql/src/pl/plpgsql/src:
gram.y (r1.64 -> r1.65)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/gram.y.diff?r1=1.64&r2=1.65)