file.c: insert separator

* file.c (rb_sys_fail_path0): insert separator between function name
  and path name.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39755 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

file.c

@@ -109,6 +109,7 @@ static void
 rb_sys_fail_path0(const char *func_name, VALUE path)
 {
     VALUE mesg = rb_str_new_cstr(func_name);
+    rb_str_buf_cat2(mesg, ": ");
     rb_str_buf_append(mesg, path);
     rb_sys_fail_str(mesg);
 }