grand: Use "e" mode flag in fopen () call for race-free setting of the close-on-exec flag

It was missed when other fopen () call sites were converted since the code
had it written as "fopen()" (without space before the opening parenthesis).

glib/grand.c

@@ -230,7 +230,7 @@ g_rand_new (void)
 
       do
 	{
-	  dev_urandom = fopen("/dev/urandom", "rb");
+	  dev_urandom = fopen ("/dev/urandom", "rbe");
 	}
       while G_UNLIKELY (dev_urandom == NULL && errno == EINTR);