Force server unit tests to run serially.
Force server unit tests to run serially.

In case anyone gets fancy and tries to run the tests in parallel,
we want to make sure no server-side TestCases are run concurrently.
In general, parallel ctest running will be encouraged in girder
because we will have plenty of other tests that won't conflict,
e.g. front-end tests or style tests.

salamb/girder,manthey/girder,essamjoubori/girder,data-exp-lab/girder,adsorensen/girder,manthey/girder,sutartmelson/girder,salamb/girder,msmolens/girder,Kitware/girder,adsorensen/girder,chrismattmann/girder,adsorensen/girder,msmolens/girder,RafaelPalomar/girder,girder/girder,data-exp-lab/girder,kotfic/girder,chrismattmann/girder,Kitware/girder,Xarthisius/girder,jbeezley/girder,jbeezley/girder,adsorensen/girder,data-exp-lab/girder,manthey/girder,Xarthisius/girder,opadron/girder,sutartmelson/girder,jcfr/girder,kotfic/girder,data-exp-lab/girder,Xarthisius/girder,essamjoubori/girder,chrismattmann/girder,Xarthisius/girder,chrismattmann/girder,Kitware/girder,kotfic/girder,jcfr/girder,kotfic/girder,opadron/girder,opadron/girder,adsorensen/girder,jcfr/girder,RafaelPalomar/girder,chrismattmann/girder,sutartmelson/girder,data-exp-lab/girder,girder/girder,salamb/girder,salamb/girder,sutartmelson/girder,kotfic/girder,Kitware/girder,manthey/girder,salamb/girder,Xarthisius/girder,essamjoubori/girder,msmolens/girder,jcfr/girder,opadron/girder,RafaelPalomar/girder,sutartmelson/girder,jcfr/girder,msmolens/girder,RafaelPalomar/girder,msmolens/girder,jbeezley/girder,girder/girder,essamjoubori/girder,girder/girder,essamjoubori/girder,opadron/girder,RafaelPalomar/girder,jbeezley/girder