chore(travis): fix deployment of jenkins branch for bugfix tags

Bugfix tags contain backported patches, and thus they aren't shown by
the `git describe`. Thus trust that Travis provides correct branch name
for the tag to push to `for-jenkins-release` branch.

.travis/deploy-jenkins-branch.sh

@@ -31,7 +31,7 @@ main() {
     fi
 
     cd qTox
-    git checkout $(git describe --abbrev=0) -b for-jenkins-release
+    git checkout "$TRAVIS_BRANCH" -b for-jenkins-release
     git push --force "https://${GH_DEPLOY_JENKINS}@github.com/qTox/qTox.git"
 }
 main