Fix link to docs in .travis.yml

Author: tailhook

.travis.yml

@@ -15,7 +15,7 @@ after_success: |
   [ $TRAVIS_BRANCH = master ] &&
   [ $TRAVIS_PULL_REQUEST = false ] &&
   cargo doc &&
-  echo "<meta http-equiv=refresh content=0;url=`echo $TRAVIS_REPO_SLUG | cut -d '/' -f 2`/index.html>" > target/doc/index.html &&
+  echo "<meta http-equiv=refresh content=0;url=`echo $TRAVIS_REPO_SLUG | cut -d '/' -f 2 | tr '-' '_'`/index.html>" > target/doc/index.html &&
   pip install ghp-import --user &&
   ~/.local/bin/ghp-import -n target/doc &&
   git push -fq https://${GH_TOKEN}@github.com/${TRAVIS_REPO_SLUG}.git gh-pages