Move utils from network stack to libs.

This package is using some common utilities from
a library that used to live in the network stack.
A better home for these utilities is frameworks/libs,
so this topic moves the files ther and also changes
the package of some utilities.

See aosp/1350222 and aosp/1350182 for a detailed
description of the specific files that moved.

Test: checkbuild
Original-change: aosp/1350083
Merged-In: I76a9b7790f3997e3e6b3c2f75ba6308286457cde
Change-Id: I76a9b7790f3997e3e6b3c2f75ba6308286457cde

Tethering/Android.bp

@@ -31,6 +31,7 @@ java_defaults {
         "android.hardware.tetheroffload.config-V1.0-java",
         "android.hardware.tetheroffload.control-V1.0-java",
         "net-utils-framework-common",
+        "net-utils-device-common",
     ],
     libs: [
         "framework-statsd.stubs.module_lib",