[grilo] travis: build documentation

[Juan A. Suárez Romero <jasuarez src gnome org>]

commit ce1fa94cc8759616a6aacfe94c09ffbf3432f7c0
Author: Juan A. Suarez Romero <jasuarez igalia com>
Date:   Wed Feb 8 10:14:39 2017 +0100

    travis: build documentation

 .travis.yml |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/.travis.yml b/.travis.yml
index f9e1f0b..6b43172 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,5 +9,5 @@ before_install:
          gobject-introspection libgirepository1.0-dev zlib1g-dev
          libtotem-plparser-dev
 script:
-  - ./autogen.sh
+  - ./autogen.sh --enable-gtk-doc
   - make