set the distribution to be precise

travis_custom/custom_before_install

@@ -29,6 +29,9 @@ export GIT_DEPENDENCIES=$GIT_DEPENDENCIES" https://github.com/laas/simple_humano
 # When this script is called the current directory is ./custom_travis
 . ./.travis/run ../.travis/before_install
 
+# Set the distrivution to be precise
+export DIST="precise"
+
 # End debug mode
 set +v
 set +x