Makefile: have python scripts depend on NO_PYTHON setting

Like the perl scripts, python scripts need a dependency to ensure they
are rebuilt when switching between the "dummy" versions that run
without Python and the real thing.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -1861,6 +1861,9 @@ $(SCRIPT_PERL_GEN) git-instaweb: % : unimplemented.sh
 	mv $@+ $@
 endif # NO_PERL
 
+# This makes sure we depend on the NO_PYTHON setting itself.
+$(SCRIPT_PYTHON_GEN): GIT-BUILD-OPTIONS
+
 ifndef NO_PYTHON
 $(SCRIPT_PYTHON_GEN): GIT-CFLAGS GIT-PREFIX GIT-PYTHON-VARS
 $(SCRIPT_PYTHON_GEN): % : %.py