help: release strbuf on error return in exec_man_konqueror()

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/help.c

@@ -152,6 +152,7 @@ static void exec_man_konqueror(const char *path, const char *page)
 		strbuf_addf(&man_page, "man:%s(1)", page);
 		execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 		warning_errno(_("failed to exec '%s'"), path);
+		strbuf_release(&man_page);
 	}
 }