fix class reference

plugin.xml

@@ -1,5 +1,5 @@
 <?xml version='1.0' encoding='utf-8'?>
-<plugin id="cordova-plugin-firebase" version="0.1.7" xmlns="http://apache.org/cordova/ns/plugins/1.0" 
+<plugin id="cordova-plugin-firebase" version="0.1.7" xmlns="http://apache.org/cordova/ns/plugins/1.0"
 xmlns:android="http://schemas.android.com/apk/res/android">
 	<name>Google Firebase Plugin</name>
 
@@ -16,7 +16,7 @@ xmlns:android="http://schemas.android.com/apk/res/android">
 	<platform name="android">
 		<config-file parent="/*" target="res/xml/config.xml">
 			<feature name="FirebasePlugin">
-				<param name="android-package" value="org.apache.cordova.firebase.FirebasePlugin" />
+				<param name="android-package" value="org.apache.cordova.firebase.FirebasePlugin.FirebasePlugin" />
 				<param name="onload" value="true" />
 			</feature>
 		</config-file>
@@ -39,7 +39,7 @@ xmlns:android="http://schemas.android.com/apk/res/android">
 		<source-file src="src/android/FirebasePlugin.java" target-dir="src/org/apache/cordova/firebase/FirebasePlugin" />
 		<source-file src="src/android/FirebasePluginInstanceIDService.java" target-dir="src/org/apache/cordova/firebase/FirebasePlugin" />
 		<source-file src="src/android/FirebasePluginMessagingService.java" target-dir="src/org/apache/cordova/firebase/FirebasePlugin" />
- 
+
 		<framework src="src/android/build.gradle" custom="true" type="gradleReference" />
 		<framework src="com.google.firebase:firebase-core:9.0.2" />
 		<framework src="com.google.firebase:firebase-messaging:9.0.2" />