don't call Pie.plot in subplot loop:

- this didn't cause any errors, but is unnecessary.

Author: etpinard

src/plot_api/plot_api.js

@@ -312,7 +312,8 @@ Plotly.plot = function(gd, data, layout, config) {
 
             for(j = 0; j < modules.length; j++) {
                 _module = modules[j];
-                if(!_module.plot) continue;
+
+                if(!_module.plot && (_module.name === 'pie')) continue;
 
                 // plot all traces of this type on this subplot at once
                 cdModule = getCdModule(cdSubplot, _module);