Ooyala video field selection on the Ooyala chapter marker field configuration page won't always have all video fields

Steps to reproduce:
1. Create a Ooyala video field on one content type.
2. Also add that same field to a second content type (without creating a new one).
3. Add a Chapter markers field to that second content type.
4. When configuring the Chapter markers field, the Ooyala video field dropdown will be empty, even though there is an Ooyala video field associated with that content type.

A patch is attached.