conn: add new method SessionBusPrivateNoAutoStartup
conn: add new method SessionBusPrivateNoAutoStartup

SessionBusPrivate automatically launches dbus-launch when the other
detection mechanisms fail.  SessionBusPrivateNoAutoStartup returns an
error without executing a new process, so that it is not leaked.

Closes: https://github.com/godbus/dbus/issues/268

Signed-off-by: Giuseppe Scrivano <20002b7b24c75512093a71a58285826d5c504fca@redhat.com>

godbus/dbus