Revert "Don't custom button props over the bridge (#2174)" (#2177)

This reverts commit e69f3801b9.

src/Navigation.js

       constructor(props) {
         super(props);
         this.state = {
-          internalProps: {...props, ...PropRegistry.load(props.screenInstanceID || props.passPropsKey)}
+          internalProps: {...props, ...PropRegistry.load(props.screenInstanceID)}
         }
       }
 
       componentWillReceiveProps(nextProps) {
         this.setState({
-          internalProps: {...PropRegistry.load(this.props.screenInstanceID || props.passPropsKey), ...nextProps}
+          internalProps: {...PropRegistry.load(this.props.screenInstanceID), ...nextProps}
         })
       }
 

src/deprecated/platformSpecificDeprecated.android.js

 import React, {Component} from 'react';
 import ReactNative, {AppRegistry, NativeModules, processColor} from 'react-native';
 import _ from 'lodash';
-import PropRegistry from './../PropRegistry';
 
 import Navigation from './../Navigation';
 
       if (button.buttonColor) {
         button.color = processColor(button.buttonColor);
       }
-      if (button.component) {
-        const passPropsKey = _.uniqueId('customButtonComponent');
-        PropRegistry.save(passPropsKey, button.passProps);
-        button.passProps = {passPropsKey};
-      }
     });
   }
   let leftButton = getLeftButton(params);