[FIX] web_editor: strange horizontal scroll on mousedown

Before this commit, when pressing the mouse button on the end of the
ace editor, it scrolled to the right, selecting the whole sentence
end. This strange behavior was due to some initialization mistake
made by commit https://github.com/odoo/odoo/commit/5a030db3eb77b6d80187f8ae1a64303b2f50391d

addons/web_editor/static/src/js/ace.js

@@ -107,12 +107,11 @@ var ViewEditor = Widget.extend({
      */
     start: function () {
         this.$viewEditor = this.$('#ace-view-editor');
-        this.$editor = this.$(".ace_editor");
         this.$viewList = this.$('#ace-view-list');
         this.$viewID = this.$('#ace-view-id');
-
         this.aceEditor = window.ace.edit(this.$viewEditor[0]);
         this.aceEditor.setTheme("ace/theme/monokai");
+        this.$editor = this.$(".ace_editor");
 
         var refX = 0;
         var resizing = false;