package/kodi: fix leftover instance of 'xbmc'

During the XBMC -> Kodi rename, some instance of 'xbmc' were left out,
which meant our startup script would not run Kodi, and that Kodi would
create its /.kodi directory.

This patch renames the missing bits.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>