snapshot - src: Changed reference to the constant PG_DATETIME to

Log Message:
-----------
Changed reference to the constant PG_DATETIME to PG_TIMESTAMP since it has been removed on recent DBD::Pg versions.

Modified Files:
--------------
src/pl:
map2PgType.pl (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/snapshot/src/pl/map2PgType.pl.diff?r1=1.4&r2=1.5)
getUnifiedSqlType.pl (r1.3 -> r1.4)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/snapshot/src/pl/getUnifiedSqlType.pl.diff?r1=1.3&r2=1.4)