allow alternativ API for getting server config
allow alternativ API for getting server config

seems, lately an alternative API for getting the server config has been
implemented and the code path when running the tests, executed this
query. The fakeserver to start up the ui therefore needs to handle this
situation, too.

Fixes broken startup with latest 7.8.0 release of AppSuite

Open-Xchange-Frontend/karma-ox-ui