CRI on attempting to change a pixmap's client when pixmap already has client

this should never occur, so do something if it does since it means there's a big problem

src/bin/e_pixmap.c

@@ -438,6 +438,7 @@ EAPI void
 e_pixmap_client_set(E_Pixmap *cp, E_Client *ec)
 {
    EINA_SAFETY_ON_NULL_RETURN(cp);
+   if (cp->client && ec) CRI("ACK!");
    cp->client = ec;
 }