Fix subtype transaction data missing.

Test plan: change type of a task, check
with transaction.search the transaction
data exists.

src/applications/transactions/conduit/TransactionSearchConduitAPIMethod.php

@@ -260,6 +260,13 @@ EOREMARKUP
             $type = 'subscribers';
             $fields = $this->newEdgeTransactionFields($xaction);
             break;
+          case PhabricatorTransactions::TYPE_SUBTYPE:
+            $type = 'subtype';
+            $fields = array(
+              'old' => $xaction->getOldValue(),
+              'new' => $xaction->getNewValue()
+            );
+            break;
         }
       }