Add UsbDebuggingManager and UsbDebuggingActivity to LegacyUsbManager

The UsbDebuggingManager listens to adbd requests and displays a dialog
when the public key authentification fails, for the user to confirm if it
wants to allow USB debugging from the attached host. If the user chooses
to always allow USB debugging, the UsbDebuggingManager writes the public
key to adbd's config file so that the public key authenfication succeeds
next time.

	modified:   services/java/com/android/server/usb/LegacyUsbDeviceManager.java

https://github.com/CyanogenMod/android_frameworks_base/commit/489e29b0ae218da797b832d9abe453e4ee9e19ad

Change-Id: I33cd3a9889d8529052a872d0d71c0f7ccf932c20