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

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

@@ -5,10 +5,6 @@ final class PhabricatorWorkerActiveTask extends PhabricatorWorkerTask {
   private $serverTime;
   private $localTime;
 
-  public function getTableName() {
-    return 'worker_task';
-  }
-
   public function getConfiguration() {
     return array(
       self::CONFIG_IDS => self::IDS_COUNTER,
@@ -71,7 +67,7 @@ final class PhabricatorWorkerActiveTask extends PhabricatorWorkerTask {
   }
 
   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

@@ -10,7 +10,7 @@ final class PhabricatorWorkerArchiveTask extends PhabricatorWorkerTask {
   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

@@ -1028,6 +1028,10 @@ final class PhabricatorBuiltinPatchList extends PhabricatorSQLPatchList {
         'type'    => 'sql',
         'name'    => $this->getPatchPath('repository-lint.sql'),
       ),
+      'liskcounters-task.sql' => array(
+        'type'    => 'sql',
+        'name'    => $this->getPatchPath('liskcounters-task.sql'),
+      ),
     );
   }