Fix the "maintainer-clean" rule, and avoid maven downloads on clean

Author: Sandro Santilli

jdbc/Makefile.in

@@ -18,14 +18,15 @@ all: build
 pom.xml: pom.xml.in
 	sed 's,%VERSION%,$(POSTGIS_LIB_VERSION),g' $< >$@
 
+# nothing to do on clean
+# (better not invoke ant here, as it downloads the world
 clean:
-	: nothing to do
 
 build: pom.xml
-
-build clean distclean check:
 	$(ANT) $@
 
+distclean: clean
+
 maintainer-clean: distclean
 	rm -f pom.xml