games/quadra: Fix build with Clang 6

source/update.cpp:83:20: error: invalid suffix on literal; C++11 requires a space between literal and identifier [-Wreserved-user-defined-literal]

buf.append("GET "UPDATE_PATH" HTTP/1.0\r\n");
                 ^

source/update.cpp:84:22: error: invalid suffix on literal; C++11 requires a space between literal and identifier [-Wreserved-user-defined-literal]

buf.append("Host: "UPDATE_HOST"\r\n");
                   ^

http://beefy12.nyi.freebsd.org/data/head-amd64-default/p473592_s335809/logs/quadra-1.3.0_6.log