fix(tests): only update lastupdate file on success
fix(tests): only update lastupdate file on success

shane-tomlinson/fxa-content-server,shane-tomlinson/fxa-content-server,shane-tomlinson/fxa-content-server,vladikoff/fxa-content-server,npestana/fxa-content-server,mozilla/fxa-content-server,swatilk/fxa-content-server,npestana/fxa-content-server,vladikoff/fxa-content-server,vladikoff/fxa-content-server,mozilla/fxa-content-server,swatilk/fxa-content-server,mozilla/fxa-content-server,npestana/fxa-content-server,swatilk/fxa-content-server