ci: Drop old mercurial kludge

Author: tarsius

.github/workflows/ci.yml

@@ -26,10 +26,6 @@ jobs:
       run: |
         sudo apt-get install emacs git mercurial texinfo imagemagick
 
-        # Work around SSL-related failures, see
-        # https://stackoverflow.com/questions/21477683/mercurial-https-clone-abort-error-wrong-version-number
-        echo "[ui]\ntls = False" > $HOME/.hgrc
-
     - name: Setup config path
       run: |
         echo "LOAD_PATH = $GITHUB_WORKSPACE/package-build" > melpa/config.mk