Fixes key installation for other target urls in hack/install.sh

Docker-DCO-1.0-Signed-off-by: Jonas Pfenniger <zimbatm@zimbatm.com> (github: zimbatm)

hack/install.sh

@@ -108,7 +108,11 @@ case "$lsb_dist" in
 		fi
 		(
 			set -x
-			$sh_c "apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9"
+			if [ "https://get.docker.io/" = "$url" ]; then
+				$sh_c "apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9"
+			else
+				$sh_c "$curl ${url}gpg | apt-key add -"
+			fi
 			$sh_c "echo deb ${url}ubuntu docker main > /etc/apt/sources.list.d/docker.list"
 			$sh_c 'sleep 3; apt-get update; apt-get install -y -q lxc-docker'
 		)