[facenet] Allow for layer name to be provided as well

Status Job ID Name Coverage
  Build
passed #146181
docker
build_linux_27

00:12:34

passed #146182
docker
build_linux_36

00:13:50

passed #146357
macosx
build_macosx_27

00:12:11

passed #146356
macosx
build_macosx_36

00:11:38

failed #146183
macosx
build_macosx_27

00:01:11

failed #146184
macosx
build_macosx_36

00:01:12