Fix handling of Phriction conduit edits

Summary: See https://discourse.phabricator-community.org/t/conduit-method-phriction-edit-requires-title-while-the-docs-say-its-optional/2176. Make code consistent with documentation by not requiring either `content` or `title`.

Test Plan: Hit the method via the UI and no longer got an error on missing `content` or `title` fields.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D19862

src/applications/phriction/conduit/PhrictionEditConduitAPIMethod.php

@@ -41,12 +41,19 @@ final class PhrictionEditConduitAPIMethod extends PhrictionConduitAPIMethod {
     }
 
     $xactions = array();
+    if ($request->getValue('title')) {
       $xactions[] = id(new PhrictionTransaction())
-      ->setTransactionType(PhrictionDocumentTitleTransaction::TRANSACTIONTYPE)
+        ->setTransactionType(
+          PhrictionDocumentTitleTransaction::TRANSACTIONTYPE)
         ->setNewValue($request->getValue('title'));
+    }
+
+    if ($request->getValue('content')) {
       $xactions[] = id(new PhrictionTransaction())
-      ->setTransactionType(PhrictionDocumentContentTransaction::TRANSACTIONTYPE)
+        ->setTransactionType(
+          PhrictionDocumentContentTransaction::TRANSACTIONTYPE)
         ->setNewValue($request->getValue('content'));
+    }
 
     $editor = id(new PhrictionTransactionEditor())
       ->setActor($request->getUser())