Use /changes/{id}/revisions/{sha1}/submit to submit changes

Replace the legacy JSON-RPC invocation with a new REST style API that
names the patch set being submitted in the URI. Callers that don't
care can use /changes/{id}/submit to submit whatever the current patch
set is at the time the call starts at the server.

The input is trivial, an optional boolean indicating if the caller
wants to wait for the merge operation to execute now, or just have
it schedule in the background to complete some time later. Web UI
and SSH both set wait_for_merge true to match the old behavior.

The logic to identify an error message written by the server is now
part of the server rather than being buried in the client UI and is
also now reported over SSH if there is an error.

Change-Id: Ibade3bda3e716c789522da7ce14b284e07df08bc

gerrit-common/src/main/java/com/google/gerrit/common/data/ChangeManageService.java

@@ -25,10 +25,6 @@ import com.google.gwtjsonrpc.common.RpcImpl.Version;
 
 @RpcImpl(version = Version.V2_0)
 public interface ChangeManageService extends RemoteJsonService {
-  @Audit
-  @SignInRequired
-  void submit(PatchSet.Id patchSetId, AsyncCallback<ChangeDetail> callback);
-
   @Audit
   @SignInRequired
   void createNewPatchSet(final PatchSet.Id patchSetId, final String newCommitMessage,