Remove lock files for Coursier in Travis

Author: ashawley

.travis.yml

@@ -45,6 +45,7 @@ script:
 before_cache:
   - find $HOME/.sbt -name "*.lock" | xargs rm
   - find $HOME/.ivy2/cache -name "ivydata-*.properties" | xargs rm
+  - find $HOME/.coursier -name "*.lock" | xargs rm
 cache:
   directories:
     - $HOME/.ivy2/cache