Ignore shellcheck errors in admin ssh keys, fix test ssh connection

ssh without -n or </dev/null will eat all input from the while read loop
This stopped the tests in the test ssh connection to be run

see man ssh for the -n option

bin/admin-remove-old-ssh-keys.sh

@@ -54,6 +54,7 @@ if [ ! -f "${CONFIG_BASE}settings.ini" ]; then
 	exit;
 fi
 # shellcheck source=../config/settings.ini
+# shellcheck disable=SC1094
 source <(grep "=" "${CONFIG_BASE}settings.ini" | sed 's/ *= */=/g')
 if [ -z "${key_age}" ]; then
 	echo "A minimnum key age in days must be set in the settings";
@@ -78,7 +79,7 @@ fi
 
 # default ssh command
 # -t is needed for systens when "Defaults    requiretty" is set
-SSH="ssh -a -x";
+SSH="ssh -a -x -n";
 
 remove_ssh_key() {
 	AUTH_KEY_FILE="${1}";