hmi-controller: Set initialized-flag when UI settings succeeded.

> So, if getting any single id from the config fails, you ignore them all,
> do not set up any of the UI components except launchers, and then
>     continue as if nothing went wrong? Seems a bit strange, but if you
>     like it that way, so be it.

Signed-off-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>
ivi-shell: Replace weston_client_launch() with weston_client_start()

> Since you are not really using the SIGCHLD handler for anything, a
> better function to call would be weston_client_start().
> Allows you to remove the 'process' field from struct hmi_controller

Signed-off-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>