Realm names defined for tests are used in main Mesos code

In process/gtest.hpp the realms READONLY_HTTP_AUTHENTICATION_REALM and READWRITE_HTTP_AUTHENTICATION_REALM are defined. These are then used in master/main.cpp and slave/main.cpp. I'd expect that these would only be used in tests or these realms should be defined elsewhere.
Also the concept of having these two realms seems specific to Mesos, not libprocess, hence it would make sense to define them somewhere in Mesos.