Makefile: improve JAVA_HOME check

On Fedora it often happens that the $JAVA_HOME directory is not actually
deleted but contains a bunch of ".rpmnew" and ".rpmsave" files in
jre/lib/security - so check that the "include" directory exists.

Change-Id: I34bf945b346e79dbe6f1a6e96ba1ba5139ff8f13
Reviewed-on: https://gerrit.libreoffice.org/28491Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>

Makefile.in

@@ -47,7 +47,7 @@ $(BUILDDIR)/config_host.mk : $(wildcard \
 		$(BUILDDIR)/autogen.sh \
 		) \
 		$(shell . $(SRCDIR)/bin/get_config_variables JAVA_HOME && \
-			if test -n "$${JAVA_HOME}" -a ! -d "$${JAVA_HOME}"; then echo force-restart; fi)
+			if test -n "$${JAVA_HOME}" -a ! -d "$${JAVA_HOME}/include"; then echo force-restart; fi)
 	sh -c $(SRCDIR)/autogen.sh
 
 else # MAKE_RESTARTS