ref_gl: gl_rlight: fixed game crash in Customize multiplayer menu

ref_gl/gl_rlight.c

@@ -153,6 +153,7 @@ void R_PushDlights( void )
 	tr.dlightframecount = tr.framecount;
 
 	RI.currententity = gEngfuncs.GetEntityByIndex( 0 );
+	if( RI.currententity )
 		RI.currentmodel = RI.currententity->model;
 
 	for( i = 0; i < MAX_DLIGHTS; i++, l++ )
@@ -165,6 +166,7 @@ void R_PushDlights( void )
 		if( GL_FrustumCullSphere( &RI.frustum, l->origin, l->radius, 15 ))
 			continue;
 
+		if( RI.currententity )
 			R_MarkLights( l, 1<<i, RI.currentmodel->nodes );
 	}
 }