Escape brackets in hack/install.sh

Fixes #23260

Signed-off-by: Dimitris Rozakis <dimrozakis@gmail.com>

hack/install.sh

@@ -429,7 +429,7 @@ do_install() {
 			done
 			$sh_c "apt-key adv -k ${gpg_fingerprint} >/dev/null"
 			$sh_c "mkdir -p /etc/apt/sources.list.d"
-			$sh_c "echo deb [arch=$(dpkg --print-architecture)] ${apt_url}/repo ${lsb_dist}-${dist_version} ${repo} > /etc/apt/sources.list.d/docker.list"
+			$sh_c "echo deb \[arch=$(dpkg --print-architecture)\] ${apt_url}/repo ${lsb_dist}-${dist_version} ${repo} > /etc/apt/sources.list.d/docker.list"
 			$sh_c 'sleep 3; apt-get update; apt-get install -y -q docker-engine'
 			)
 			echo_docker_as_nonroot