Fix static variable usage in Lisk

Summary:
See comment.
This can reveal some pretty bad bugs but HPHP handles this correctly so we already know about them.

Test Plan:
Added `phlog()` to `__call()` and observed what is defined for each method (under PHP). Also:

  class C {
    function __call($name, $args) {
      static $class;
      if (!$class) {
        $class = get_class($this);
      }
      return $class;
    }
  }

  class D extends C {
  }

  class E extends C {
  }

  $d = new D;
  $e = new E;
  var_dump($d->x());
  var_dump($e->x()); // Prints D under PHP!

See also D3754.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T1261

Differential Revision: https://secure.phabricator.com/D3753

src/infrastructure/storage/lisk/LiskDAO.php

@@ -1695,6 +1695,16 @@ abstract class LiskDAO {
    */
   public function __call($method, $args) {
 
+    // NOTE: PHP has a bug that static variables defined in __call() are shared
+    // across all children classes. Call a different method to work around this
+    // bug.
+    return $this->call($method, $args);
+  }
+
+  /**
+   * @task   util
+   */
+  final protected function call($method, $args) {
     // NOTE: This method is very performance-sensitive (many thousands of calls
     // per page on some pages), and thus has some silliness in the name of
     // optimizations.