install some more docbook files to avoid fetches on travis.

diff --git a/.travis.yml b/.travis.yml
index d521c8bf1e0c5223ecda3e38e0464a097b6e9db4..de45387ef3ef0678f3b8c85001660f412c54de88 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -18,6 +18,7 @@ addons:
     - qttools5-dev-tools
     - qttranslations5-l10n
     - libusb-dev
+    - docbook-xml
     - docbook-xsl
 script:
  - ./build_and_test