Restore "Create" transactions

Summary:
Ref T10004. This restores "alice created this task." transactions, but in a generic way so we don't have to special case one of the other edits with an old `null` value.

In most cases, creating an object now shows only an "alice created this thing." transaction, unless nonempty defaults (usually, policy or spaces) were adjusted.

Test Plan: Created pastes, tasks, blogs, packages, and forms. Saw a single "alice created this thing." transaction.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10004

Differential Revision: https://secure.phabricator.com/D14820

src/applications/phame/storage/PhameBlogTransaction.php

@@ -24,7 +24,9 @@ final class PhameBlogTransaction
     $old = $this->getOldValue();
     switch ($this->getTransactionType()) {
       case self::TYPE_DESCRIPTION:
-        return ($old === null);
+        if ($old === null) {
+          return true;
+        }
     }
     return parent::shouldHide();
   }
@@ -98,6 +100,10 @@ final class PhameBlogTransaction
 
     $type = $this->getTransactionType();
     switch ($type) {
+      case PhabricatorTransactions::TYPE_CREATE:
+        return pht(
+          '%s created this blog.',
+          $this->renderHandleLink($author_phid));
       case self::TYPE_NAME:
         if ($old === null) {
           return pht(