Fix errors reported by the no-extra-bind ESLint rule

http://eslint.org/docs/rules/no-extra-bind

web/firefoxcom.js

@@ -173,7 +173,7 @@ Preferences._readFromStorage = function (prefObj) {
       highlightAll: !!evt.detail.highlightAll,
       findPrevious: !!evt.detail.findPrevious
     });
-  }.bind(this);
+  };
 
   for (var i = 0, len = events.length; i < len; i++) {
     window.addEventListener(events[i], handleEvent);

web/secondary_toolbar.js

@@ -188,7 +188,7 @@ var SecondaryToolbar = (function SecondaryToolbarClosure() {
           toggleHandToolButton.firstElementChild.textContent =
             mozL10n.get('hand_tool_enable_label', null, 'Enable hand tool');
         }
-      }.bind(this));
+      });
     },
 
     open: function SecondaryToolbar_open() {