Revert "Add deploy setup for gh-pages"

This reverts commit fb8855bffe35f809b0ca8c4ed0bf70a5423d69e9.

.travis.yml

@@ -68,15 +68,8 @@ addons:
     - libcurl4-openssl-dev
     - libelf-dev
     - libdw-dev
-after_success: |
+after_success:
-  [ $TRAVIS_BRANCH = master ] &&
+- travis-cargo --only stable doc-upload
-  [ $TRAVIS_PULL_REQUEST = false ] &&
-  cd .imag-documentation &&
-  cargo doc &&
-  echo "<meta http-equiv=refresh content=0;url=`echo $TRAVIS_REPO_SLUG | cut -d '/' -f 2 | sed 's/-/_/'`/index.html>" > target/doc/index.html &&
-  sudo pip install ghp-import &&
-  ghp-import -n target/doc &&
-  git push -fq https://${GH_TOKEN}@github.com/${TRAVIS_REPO_SLUG}.git gh-pages
 notifications:
   email:
     on_success: never