Make fix for input selection more robust (#84)

* use Meteor's internal selector instead of a global jQuery

* Make the focus input event a bit more robust

* Undo accidental cut

* code style

packages/rocketchat-ui-message/client/messageBox.js

@@ -250,13 +250,12 @@ Template.messageBox.events({
 	},
 	'focus .input-message'(event, instance) {
 		KonchatNotification.removeRoomNotification(this._id);
-		chatMessages[this._id].input = instance.find('.input-message');
-		// Created by Vignesh on 22/08/2017
-		if ($('.input-message').val() !== ''){
-			chatMessages[this._id].input.updateAutogrow();
+		const input = event.target;
+		chatMessages[this._id].input = input;
+		if (event.target.value) {
 			instance.isMessageFieldEmpty.set(false);
+			return typeof input.updateAutogrow === 'function' && input.updateAutogrow();
 		}
-		// End of creation by Vignesh on 22/08/2017
 	},
 	'click .send-button'(event, instance) {
 		const input = instance.find('.input-message');