Disable DTM regression test in postgres_fdw.

Since we disabled DTM brusquely and with fire, temporarily don't run DTM test on
postgres_fdw -- we need to make proper GUC turning it on and off.

Author: arssher

contrib/postgres_fdw/Makefile

@@ -29,5 +29,5 @@ endif
 # Poor's man overload of already defined target: just copy it
 check: submake $(REGRESS_PREP)
 	$(pg_regress_check) $(REGRESS_OPTS) $(REGRESS)
-	env DESTDIR='$(abs_top_builddir)'/tmp_install $(MAKE) install
-	$(prove_check)
+#	env DESTDIR='$(abs_top_builddir)'/tmp_install $(MAKE) install
+#	$(prove_check)