* dbus/com.ubuntu.Upstart.xml: Added "GetEnv" and "SetEnv" methods.
* init/control.c:
- control_set_env(): Implementation of "SetEnv" D-Bus method.
- control_get_env(): Implementation of "GetEnv" D-Bus method.
* init/job_class.c:
- Added job_environ environment table.
- job_class_environ_init(): Initialise job_environ.
- job_class_environment: Use job_environ.
* init/main.c: main(): Call job_class_environ_init().