Convert File.NameKey to AutoValue

Fixes this error when building in-tree with bazel:
 plugins/batch/src/main/java/com/google/gerrit/reviewdb/client/File.java:21: error: [strict] Using type com.google.gwtorm.client.StringKey from an indirect dependency (TOOL_INFO: "//java/com/google/gwtorm"). See command below **
   public static class NameKey extends StringKey<Branch.NameKey> {
                                       ^
I could have instead added the gwtorm dependency, but backporting this
sounded better to me.

Change-Id: If0110c1a391d67f2d70a3413b46e9ffe7c9e2c1c
9 files changed