Log interface hash in NetworkStack dumpsys version

The hash is logged similarly to how version code was logged, and will be
used to verify that valid interfaces are used to communicate with
NetworkStack.

Bug: 137328719
Test: atest NetworkStackTests:NetworkStackServiceTest

Original-Change: https://android-review.googlesource.com/1293755
Merged-In: I706e40dbe884ffa545f9127e29616a65d5f69c53
Change-Id: I706e40dbe884ffa545f9127e29616a65d5f69c53