prop=info&inprop=watched only works for existing pages, it doesn't show if a missing page is watched.

Steps to reproduce

1. Watch a missing page, e.g.

http://en.wikipedia.org/w/index.php?title=This_is_a_missing_page&action=watch

2. Ask the API about it:

http://en.wikipedia.org/w/api.php?action=query&prop=info&inprop=watched&titles=This_is_a_missing_page

Actual result:

<page ns="0" title="This is a missing page" missing="" />

Expected result:

<page ns="0" title="This is a missing page" missing="" watched="" />

Version: unspecified
Severity: enhancement