Fix crash on error when installing with root

[Phoenix09]

Missing argument

AndroidRuntime: FATAL EXCEPTION: main
AndroidRuntime: Process: de.robv.android.xposed.installer, PID: 13200
AndroidRuntime: java.util.MissingFormatArgumentException: Format specifier '%2$s'
AndroidRuntime:        at java.util.Formatter.format(Formatter.java)
AndroidRuntime:        at java.util.Formatter.format(Formatter.java)
AndroidRuntime:        at java.lang.String.format(String.java)
AndroidRuntime:        at android.content.res.Resources.getString(Resources.java)
AndroidRuntime:        at android.content.Context.getString(Context.java)
AndroidRuntime:        at de.robv.android.xposed.installer.util.NotificationUtil.showModuleInstallNotification(NotificationUtil.java:160)
AndroidRuntime:        at de.robv.android.xposed.installer.util.InstallApkUtil.onPostExecute(InstallApkUtil.java:102)
AndroidRuntime:        at de.robv.android.xposed.installer.util.InstallApkUtil.onPostExecute(InstallApkUtil.java:20)
AndroidRuntime:        at android.os.AsyncTask.finish(AsyncTask.java)
AndroidRuntime:        at android.os.AsyncTask.-wrap1(AsyncTask.java)
AndroidRuntime:        at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java)
AndroidRuntime:        at android.os.Handler.dispatchMessage(Handler.java)
AndroidRuntime:        at android.os.Looper.loop(Looper.java)
AndroidRuntime:        at android.app.ActivityThread.main(ActivityThread.java)
Method)
AndroidRuntime:        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java)
AndroidRuntime:        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java)
AndroidRuntime:        at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:107)

[DVDAndroid]

LGTM

[DVDAndroid]

I don't know if I'll publish a new version