Remove a potentially pre-existing server.pid in entrypoint.sh (Merge pull request #4684)

With this solution we don't need to amend the docker-compose.yml file.

scripts/entrypoint.sh

@@ -13,5 +13,13 @@ usermod -g "$USER_GID" consul 2> /dev/null
 chown -R -h "$USER_UID" "$BUNDLE_PATH"
 chgrp -R -h "$USER_GID" "$BUNDLE_PATH"
 
+# Remove a potentially pre-existing server.pid for Rails.
+set -e
+
+if [ -f tmp/pids/server.pid ]; then
+  rm tmp/pids/server.pid
+fi
+
+# Then exec the container's main process (what's set as CMD in the Dockerfile).
 /usr/bin/sudo -EH -u consul "$@"