"make clean" should clean up after a rpm build

There's a few generated files that we left behind.

Author: Linus Torvalds

Makefile

@@ -192,6 +192,7 @@ test: all
 
 clean:
 	rm -f *.o mozilla-sha1/*.o ppc/*.o $(PROG) $(LIB_FILE)
+	rm -f git-core-*.tar.gz git-core.spec
 	$(MAKE) -C Documentation/ clean
 
 backup: clean