Support podman in make dev-tor

Unfortunately `podman volume` and `docker volume` are not identical,
podman will (sensibly) error if you try to create a volume that already
exists unless you pass `--ignore`, which docker doesn't support.

So we conditionally add the needed flag depending on which tool we're
using.

securedrop/bin/dev-shell

@@ -116,7 +116,8 @@ function docker_run() {
 
     if [ -n "${USE_TOR:-}" ]; then
         # Mount persistent onion services
-        docker volume create sd-onion-services
+        # shellcheck disable=SC2046
+        $DOCKER_BIN volume create sd-onion-services $(if [ "$DOCKER_BIN" = "podman" ]; then echo "--ignore"; fi)
         DOCKER_RUN_ARGUMENTS="${DOCKER_RUN_ARGUMENTS} --volume sd-onion-services:/var/lib/tor/services"
     fi