"Angela Davis: Le combat continue"
... is a 40 minute 2011 documentary about Angela Davis - you can hear her speak in English but as it's dubbed into German you cannot always hear the English original. At 36:36 min she says that she is vegan.
Update: The video was deleted and is not currently online. But you might be able to download it somewhere. Google it. Das Video wurde gelöscht, aber man kann es eventuall woanders runterladen. Se han borrado el video, pero quizás puedes descargarlo desde otros sitios.
Update 2012: Angela Davis mentioning animal suffering, eating animals, and commodification of animals here: http://vimeo.com/37361383# (speaking at UC Davis, 23 Feb 2012)
See this blog post: http://academicabolitionistvegan.blogspot.com/2014/01/vegan-angela-davis-connects-human-and.html
or the original transcript: http://www.radioproject.org/2012/02/grace-lee-boggs-berkeley/
... confirming that Angela Davis is vegan, also some very interesting quotes by her (from the 27th Empowering Women of Color Conference, 2 March 2012)