Remove etc/ci/retry.sh

It was added with the intention of being used on the CI,
but it was never added to the CI. We have better ways of finding
test failures and intermittents these days.

etc/ci/retry.sh

@@ -1,19 +0,0 @@
-#!/usr/bin/env bash
-
-# Retries a given command until it passes
-# Run as `retry.sh N command args...`
-# where `N` is the maximum  number of tries, and `command args...` is the
-# command to run, with arguments
-
-set -o errexit
-set -o nounset
-set -o pipefail
-
-n="$1"
-shift; # this removes the first argument from $@
-for i in $(seq $n); do
-        echo "====== RUN NUMBER: $i ======";
-        # Run command and exit success if return code is 0, else ignore it
-        "$@" && exit 0 || true
-done
-exit 1