chore: cleanup post-install script (#294)

Remove keyring pulling from agent post-install scripts.

packaging/scripts/after_install.sh

@@ -25,18 +25,6 @@ main() {
 	userdel -f do-agent || true
 	useradd -s /bin/false -M --system $USERNAME || true
 
-	# TODO remove this if in next release
-	# temporarily download keys in a GPG keyring for debian based systems.
-	if command -v apt-get >/dev/null 2>&1; then
-		REPO_HOST=https://repos.insights.digitalocean.com
-		REPO_GPG_KEY=${REPO_HOST}/sonar-agent.asc
-		deb_list=/etc/apt/sources.list.d/digitalocean-agent.list
-		deb_keyfile=/usr/share/keyrings/digitalocean-agent-keyring.gpg
-		repo="do-agent"
-		echo "deb [signed-by=${deb_keyfile}] ${REPO_HOST}/apt/${repo} main main" >"${deb_list}" || true
-		curl -sL "${REPO_GPG_KEY}" | gpg --dearmor >"${deb_keyfile}" || true
-	fi
-
 	if command -v systemctl >/dev/null 2>&1; then
 		# systemd is used, remove the upstart script
 		rm -f "${INIT_SVC_FILE}"