Map the correct path to the tripal2 docker container to fix missing modules errors

.travis.yml

@@ -57,7 +57,7 @@ script:
   - mv ../tripal sites/all/modules/tripal
 
   # Run a docker container with tripal 2 pre-installed
-  - docker run -it -d --rm --name tripal2 -v "$(pwd)/tripal":/modules/tripal statonlab/tripal2
+  - docker run -it -d --rm --name tripal2 -v "$(pwd)/sites/all/modules/tripal":/modules/tripal statonlab/tripal2
 
   # Apply patches
   - wget --no-check-certificate https://drupal.org/files/drupal.pgsql-bytea.27.patch