feat: port migrate user to Rust, remove Python calling

Closes #1206

autopush_rs/src/client.rs

@@ -585,7 +585,7 @@ where
 
     #[state_machine_future(transitions(DetermineAck))]
     AwaitMigrateUser {
-        response: MyFuture<String>,
+        response: MyFuture<()>,
         data: AuthClientData<T>,
     },
 
@@ -947,11 +947,11 @@ where
         await_migrate_user: &'a mut RentToOwn<'a, AwaitMigrateUser<T>>,
     ) -> Poll<AfterAwaitMigrateUser<T>, Error> {
         debug!("State: AwaitMigrateUser");
-        let message_month = try_ready!(await_migrate_user.response.poll());
+        try_ready!(await_migrate_user.response.poll());
         let AwaitMigrateUser { data, .. } = await_migrate_user.take();
         {
             let mut webpush = data.webpush.borrow_mut();
-            webpush.message_month = message_month;
+            webpush.message_month = data.srv.opts.current_message_month.clone();
             webpush.flags.rotate_message_table = false;
         }
         transition!(DetermineAck { data })

autopush_rs/src/util/ddb_helpers.rs

@@ -1005,15 +1005,14 @@ impl DynamoStorage {
         message_month: &str,
         current_message_month: &str,
         router_table_name: &str,
-    ) -> MyFuture<String> {
+    ) -> MyFuture<()> {
         let ddb = self.ddb.clone();
         let ddb1 = self.ddb.clone();
         let ddb2 = self.ddb.clone();
         let uaid = uaid.clone();
         let cur_month = current_message_month.to_string();
         let cur_month1 = cur_month.clone();
         let cur_month2 = cur_month.clone();
-        let cur_month3 = cur_month.clone();
         let router_table_name = router_table_name.to_string();
         let response = DynamoStorage::all_channels(ddb, &uaid, message_month)
             .and_then(move |channels| -> MyFuture<_> {
@@ -1031,7 +1030,7 @@ impl DynamoStorage {
                     &cur_month2,
                 )
             })
-            .and_then(move |_| -> MyFuture<_> { Box::new(future::ok(cur_month3)) })
+            .and_then(move |_| -> MyFuture<_> { Box::new(future::ok(())) })
             .chain_err(|| "Unable to migrate user");
         Box::new(response)
     }