Add new_remote_state

Add new_remote_state

Add new_remote_state and change remote_state to be a pointer.  This is
a preparatory patch for a later series.  It could perhaps be omitted,
but new_remote_state also does some initialization that was previously
done for the globals.

	* remote.c (remote_state): Now a pointer.
	(get_remote_state_raw): Update.
	(new_remote_state): New function.
	(_initialize_remote): Use new_remote_state.