Remove Python tracebacks.

Using Docker Compose over SSH causes errors, but it's handled. The
tracebacks just make it harder to follow what's happening.

deploy

 #!/bin/sh
 set -eu
 
+_docker_compose() {
+    docker-compose "$@" 2>&1 | sed '/^  File /,+1d'
+}
+
 _check() {
-    containers="$(until docker-compose ps -q; do true; done)"
+    containers="$(until _docker_compose ps -q; do true; done)"
     # shellcheck disable=SC2086
     docker container inspect --format '{{ .State.Health.Status }}' $containers | grep -v '^healthy$'
 }
@@ -11,7 +15,7 @@ _deploy() {
     echo "Deploying to $1" >&2
     export DOCKER_HOST="ssh://$1"
     export RUNNER_NAME="$1"
-    until docker-compose up --detach --remove-orphans ; do true; done
+    until _docker_compose up --detach --remove-orphans ; do true; done
     # shellcheck disable=SC2034
     for i in $(seq 12)
     do