Don't trigger build from install target

The norm is that the install target is read only from the point of view
of the source and build directory, so avoid accidentally triggering any
build.

unix/vncserver/selinux/Makefile

@@ -23,6 +23,6 @@ clean:
 	rm -f *.pp *.pp.bz2
 	rm -rf tmp
 
-install: vncsession.pp.bz2
+install:
 	mkdir -p $(DESTDIR)$(DATADIR)/selinux/packages/targeted/
 	install vncsession.pp.bz2 $(DESTDIR)$(DATADIR)/selinux/packages/targeted/vncsession.pp.bz2