Fix several migration issues with the Task/Counter patch

Summary:
People hit three issues with D3914:

- As per T2059, we applied a schema change from a `.php` patch, which currently does not work if you use a different user to make schema changes than for normal use.
- Since the change in question is idempotent, just move it to a `.sql` patch. We'll follow up in T2059 and fix it properly.
- Rogue daemons at several installs used old code (expecting autoincrement) to insert into the new table (no autoincrement), thereby creating tasks with ID 0.
- Rename the table so they'll fail.
- This also makes the code a little more consistent.
- Some installs now have tasks with ID 0.
- Use checks against null rather than against 0 so we can process these tasks.

The major issues this fixes are the schema upgrade failure in T2059, and the infinite loops in T2072 and elsewhere.

This isn't really a fully statisfactory fix. I'll discuss some next steps in T2072.

Test Plan: Created new tasks via MetaMTA/Differential. Ran tasks with `phd debug taskmaster`. Inserted a task 0 and verified it ran and archived correctly.

Reviewers: btrahan, vrana, nh

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2072, T2059

Differential Revision: https://secure.phabricator.com/D3973

resources/sql/patches/liskcounters-task.sql

···
+ALTER TABLE `{$NAMESPACE}_worker`.worker_task
+  CHANGE id id INT UNSIGNED NOT NULL;
+
+RENAME TABLE `{$NAMESPACE}_worker`.worker_task
+  TO `{$NAMESPACE}_worker`.worker_activetask;
+
+UPDATE `{$NAMESPACE}_worker`.lisk_counter
+  SET counterName = 'worker_activetask' WHERE counterName = 'worker_task';

resources/sql/patches/liskcounters.php

···
 $active_table = new PhabricatorWorkerActiveTask();
 $archive_table = new PhabricatorWorkerArchiveTask();
 
+$old_table = 'worker_task';
+
 $conn_w = $active_table->establishConnection('w');
 
 $active_auto = head(queryfx_one(
···
   'SELECT auto_increment FROM information_schema.tables
     WHERE table_name = %s
     AND table_schema = DATABASE()',
-  $active_table->getTableName()));
+  $old_table));
 
 $active_max = head(queryfx_one(
   $conn_w,
   'SELECT MAX(id) FROM %T',
-  $active_table->getTableName()));
+  $old_table));
 
 $archive_max = head(queryfx_one(
   $conn_w,
···
     VALUES (%s, %d)
     ON DUPLICATE KEY UPDATE counterValue = %d',
   LiskDAO::COUNTER_TABLE_NAME,
-  $active_table->getTableName(),
+  $old_table,
   $initial_counter + 1,
   $initial_counter + 1);
-
-// Drop AUTO_INCREMENT from the ID column.
-queryfx(
-  $conn_w,
-  'ALTER TABLE %T CHANGE id id INT UNSIGNED NOT NULL',
-  $active_table->getTableName());

src/infrastructure/daemon/workers/storage/PhabricatorWorkerActiveTask.php

···
   private $serverTime;
   private $localTime;
 
-  public function getTableName() {
-    return 'worker_task';
-  }
-
   public function getConfiguration() {
     return array(
       self::CONFIG_IDS => self::IDS_COUNTER,
···
   }
 
   public function archiveTask($result, $duration) {
-    if (!$this->getID()) {
+    if ($this->getID() === null) {
       throw new Exception(
         "Attempting to archive a task which hasn't been save()d!");
     }

src/infrastructure/daemon/workers/storage/PhabricatorWorkerArchiveTask.php

···
   protected $result;
 
   public function save() {
-    if (!$this->getID()) {
+    if ($this->getID() === null) {
       throw new Exception(
         "Trying to archive a task with no ID.");
     }

src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php

···
         'type'    => 'sql',
         'name'    => $this->getPatchPath('repository-lint.sql'),
       ),
+      'liskcounters-task.sql' => array(
+        'type'    => 'sql',
+        'name'    => $this->getPatchPath('liskcounters-task.sql'),
+      ),
     );
   }