lightmediascanner: change scan path

lightmediascanner: change scan path

Since udisks + devmon mounts in /media for security reasons we need to
scan that path.

Change-Id: I6d53a76128af579f0c14064756d7b4ec935356cf
Bug-AGL: SPEC-634
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/9605
Tested-by: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
ci-image-build: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
ci-image-boot-test: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>