vib example client on product

Bug: partner question
Test: # PRODUCT_PACKAGES += ExampleVibratorJavaProductClient
    adb root
    adb setenforce 0 # for find permission
    adb shell am start -n example.vib/example.vib.MyActivity
    # vibrator works

Change-Id: Ie70f4cfe0f546a43a5d11bbdd1f1143d817aab50