Subscription graph has a factory, but there is an extra layer of
indirection to take config into account. This indirection is inside
submoduleOp. SubmoduleOp needs the subscription graph but shouldn't
control its instantiation.
Move this to an extra Factory, so clients can instantiate their
subscription graph without depending on submoduleOp.
In guice, bind the unnannotated Subscription.Factory to the configured
factory and annotate the "vanilla" version.
Change-Id: Ie1ab3bfaebbe0480a5e4f93bbb5796b5e6a8e740
8c05f63809