Remove rubyspec temporary directory

common.mk

@@ -823,6 +823,7 @@ test-spec: $(TEST_RUNNABLE)-test-spec
 yes-test-spec: test-spec-precheck
 	$(gnumake_recursive)$(Q) \
 	$(RUNRUBY) -r./$(arch)-fake $(srcdir)/spec/mspec/bin/mspec run -B $(srcdir)/spec/default.mspec $(MSPECOPT) $(SPECOPTS)
+	$(RMDIR) rubyspec_temp
 no-test-spec:
 
 RUNNABLE = $(LIBRUBY_RELATIVE:no=un)-runnable