Fix eslint no-plusplus in es5 files

[MAILPOET-1145]

.eslintrc.es5.json

@@ -31,7 +31,6 @@
     "no-empty": 0,
     "no-useless-escape": 0,
     "wrap-iife": 0,
-    "no-plusplus": 0,
     "brace-style": 0,
     "space-infix-ops": 0
   }

assets/js/src/form_editor/form_editor.js

@@ -47,7 +47,8 @@ function info(value) {
       var length = methods.length;
       var console = {};
       window.console = {};
-      while (length--) {
+      while (length) {
+        length -= 1;
         console[methods[length]] = noop;
       }
     }());
@@ -404,7 +405,7 @@ WysijaForm = {
         blockData.position = position;
 
         // increment position
-        position++;
+        position += 1;
 
         // add block data to body
         data.body.push(blockData);
@@ -513,7 +514,8 @@ WysijaForm = {
     WysijaForm.locks.dragging = false;
 
     WysijaForm.getBlocks().each(function (container) {
-      container.setPosition(index++);
+      container.setPosition(index);
+      index += 1;
       // remove z-index value to avoid issues when resizing images
       if (container.block !== undefined) {
         container.block.element.setStyle({

assets/js/src/handlebars_helpers.js

@@ -5,7 +5,7 @@ define('handlebars_helpers', ['handlebars'], function (Handlebars) {
     var size = (arguments.length - 1);
     var output = '';
     var i;
-    for (i = 0; i < size; i++) {
+    for (i = 0; i < size; i += 1) {
       output += arguments[i];
     }
     return output;

assets/js/src/jquery.serialize_object.js

@@ -73,7 +73,7 @@ define(
           //   object or array based on the type of the next keys part.
           // * Move the 'cur' pointer to the next level.
           // * Rinse & repeat.
-          for (; i <= keysLast; i++) {
+          for (; i <= keysLast; i += 1) {
             key = keys[i] === '' ? cur.length : keys[i];
             cur[key] = i < keysLast
               ? cur[key] || (keys[i + 1] && isNaN(keys[i + 1]) ? {} : [])

assets/js/src/subscribers/importExport/import.js

@@ -1080,7 +1080,7 @@ define(
                     );
                   }
                 });
-                batchNumber++;
+                batchNumber += 1;
               });
             });