Update apt-get before installing things on CI

circle.yml

@@ -9,6 +9,7 @@ dependencies:
 
   pre:
     - sudo pip install autobahntestsuite
+    - sudo apt-get update
     - sudo apt-get install autoconf2.59
     - cd $HOME/bin && ln -s /usr/bin/autoconf2.59 autoconf
     - cd $HOME/bin && ln -s /usr/bin/autoheader2.59 autoheader