Make PM#registerDexModule oneway

The binder call should be one way.

Test: adb  shell am instrument -e class
'android.content.pm.PackageManagerTests' -w
'com.android.frameworks.coretests/android.support.test.runner.AndroidJUnitRunner'
Bug: 37290820

Change-Id: I15a5160a3b6fdc5243df7bba6e61a5e2cc4656e6