TST: Always delete extra cache files on Travis.

QuLogic · QuLogic · commit 65e3e9abca3a · 2017-03-03T00:01:05.000-05:00
Note, we don't need to do this on AppVeyor because the cache directories
are different.
diff --git a/.travis.yml b/.travis.yml
@@ -178,6 +178,8 @@ script:
       pip install $PRE requests==2.9.2 linkchecker
       linkchecker build/html/index.html
     fi
+
+before_cache:
   - rm -rf $HOME/.cache/matplotlib/tex.cache
   - rm -rf $HOME/.cache/matplotlib/test_cache
 
