[IMP] web_m2x_options: Perf issue https://github.com/OCA/web/issues/615

* fix unecessary calls

Do check_access_rights and disable_quick_create calls only once per field.

web_m2x_options/static/src/js/form.js

@@ -113,7 +113,7 @@ odoo.define('web_m2x_options.web_m2x_options', function (require) {
             if (_.isUndefined(this.view))
                     return this._super.apply(this, arguments);
                 if (!_.isUndefined(this.view.ir_options['web_m2x_options.limit'])) {
-                this.limit = parseInt(this.view.ir_options['web_m2x_options.limit']);
+                this.limit = parseInt(this.view.ir_options['web_m2x_options.limit'], 10);
             }
 
             if (typeof this.options.limit === 'number') {
@@ -136,13 +136,14 @@ odoo.define('web_m2x_options.web_m2x_options', function (require) {
                 'ilike', this.limit + 1,
                 self.build_context()));
 
-            var create_rights;
             if (!(self.options && (self.is_option_set(self.options.create) || self.is_option_set(self.options.create_edit)))) {
-                create_rights = new Model(this.field.relation).call(
+                this.create_rights = this.create_rights || (function(){
+                return new Model(self.field.relation).call(
                     "check_access_rights", ["create", false]);
+                })();
             }
 
-            $.when(search_result, create_rights).then(function (data, can_create) {
+            $.when(search_result, this.create_rights).then(function (data, can_create) {
 
                 self.can_create = can_create;  // for ``.show_error_displayer()``
                 self.last_search = data;
@@ -318,7 +319,7 @@ odoo.define('web_m2x_options.web_m2x_options', function (require) {
             // returned.
 
             if (!_.isUndefined(this.view.ir_options['web_m2x_options.limit'])) {
-                this.limit = parseInt(this.view.ir_options['web_m2x_options.limit']);
+                this.limit = parseInt(this.view.ir_options['web_m2x_options.limit'], 10);
             }
 
             if (typeof this.options.limit === 'number') {
@@ -408,7 +409,7 @@ odoo.define('web_m2x_options.web_m2x_options', function (require) {
             var open = (self.options && self.is_option_set(self.options.open));
             if(open){
                 self.mutex.exec(function(){
-                    var id = parseInt($(ev.currentTarget).data('id'));
+                    var id = parseInt($(ev.currentTarget).data('id'), 10);
                     self.do_action({
                         type: 'ir.actions.act_window',
                         res_model: self.field.relation,