remove max children limitation on SwipeableQuickActions

Summary:
**motivation**
Right now `SwipeableQuickActions` only allows two actions. Let this limit be in the userland.

cc fred2028
Closes https://github.com/facebook/react-native/pull/8528

Differential Revision: D4211729

Pulled By: ericvicenti

fbshipit-source-id: 903592190b9855ffe9da44864cdc276bc1e18a7c

Libraries/Experimental/SwipeableRow/SwipeableQuickActions.js

@@ -27,8 +27,6 @@ const React = require('React');
 const StyleSheet = require('StyleSheet');
 const View = require('View');
 
-const MAX_QUICK_ACTIONS = 2;
-
 /**
  * A thin wrapper around standard quick action buttons that can, if the user
  * chooses, be used with SwipeableListView. Sample usage is as follows, in the
@@ -53,7 +51,7 @@ class SwipeableQuickActions extends React.Component {
 
     // Multiple children
     if (children instanceof Array) {
-      for (let i = 0; i < children.length && i < MAX_QUICK_ACTIONS; i++) {
+      for (let i = 0; i < children.length; i++) {
         buttons.push(children[i]);
 
         // $FlowFixMe found when converting React.createClass to ES6