test phpcassa in hhvm, changed some phpunit settings crashing

hhvm is getting momentum these days, probably worth add testing the library with it

almost everything works perfectly, with the exception of some warning "HipHop Warning: Host lookup failed [-10001]: Unknown error -10001 in /home/travis/build/ricardclau/phpcassa/lib/Thrift/Transport/TSocket.php on line 226"

I had to remove the 2 phpunit.xml options because it was failing on hhvm. This is really weird, since they are the default options and actually the output is exactly the same