Add more details to divergent vndk lib error.

Bash better broadcast better build-backstop baggage because baffled
beings' bewilderement begets badness.

Fixes: 162379658
Test: view error by removing "libbinder" from
  VndkMustUseVendorVariantList.
Change-Id: Ib425e30bc7b5388b78af4bfab84dd24072d550a6