Function foreachkey

src/tests/environment.cpp:1144–1148

Clear any MESOS_ environment variables so they don't affect our tests.

{
  // Clear any MESOS_ environment variables so they don't affect our tests.
  foreachkey (const string& key, os::environment()) {
    if (key.find("MESOS_") == 0) {
      os::unsetenv(key);
    }
  }

  // Set the path to the native JNI library for running JVM tests.
  // TODO(tillt): Adapt library towards JNI specific name once libmesos