wireless_connection tests pass even when the connection test failed

Running the various wireless_connection tests results in the tests passing, even though the output given in the submission is something like:

 Failed to activate ubuntu-cert-bg-open. No Internet connection

This is likely to be because the return code used to judge the test results is the last one here:

create_connection $WPA_BG_SSID --security=wpa --key=$WPA_BG_PSK; internet_test --interface=`nmcli dev status | awk '/802-11-wireless/ {print $1}'`; rm -f /etc/NetworkManager/system-connections/$WPA_BG_SSID

that is the rm -rf command.

If internet_test fails then the whole test should fail.