Remove the key when we're done with it

Author: alexcrichton

ci/setup-git.sh

@@ -5,5 +5,6 @@ export GIT_SSH_COMMAND="ssh -o StrictHostKeyChecking=no"
 echo $GITHUB_DEPLOY_KEY | base64 -d > _the_key
 chmod 600 _the_key
 ssh-add _the_key
+rm _the_key
 git config --global user.name "Deploy from CI"
 git config --global user.email ""