remove install.1 on make uninstall

Just a minor fix since xinstall.1 is installed as install.1.
diff --git a/Makefile b/Makefile
index a1d5353..9ec9990 100644
--- a/Makefile
+++ b/Makefile
@@ -223,7 +223,7 @@
 
 uninstall:
 	cd $(DESTDIR)$(PREFIX)/bin && rm -f $(BIN) [ install
-	cd $(DESTDIR)$(MANPREFIX)/man1 && rm -f $(MAN)
+	cd $(DESTDIR)$(MANPREFIX)/man1 && rm -f $(MAN) install.1
 
 dist: clean
 	mkdir -p sbase-$(VERSION)