R1:6a8f31a0ecbc

Fix undefined variable

Summary:
I am hitting this error when generating Diviner documentation:

```
COMMAND
'/usr/src/phabricator/bin/diviner' atomize --ugly --book $SOME_BOOK --atomizer 'DivinerPHPAtomizer' -- $SOME_PATHS

STDOUT
(empty)

STDERR
[2015-02-18 23:05:01] EXCEPTION: (RuntimeException) Undefined variable: type at [<phutil>/src/error/PhutilErrorHandler.php:210]
#0 PhutilErrorHandler::handleError(integer, string, string, integer, array) called at…