init: Use updated boot splash image.
init: Use updated boot splash image.

Rather than using the login_splash.png file provided by the
chromeos-assets package, this makes us load the (properly
centered) boot_splash.png file that I just added via the
chromeos-assets-split package, which can be overlaid to
provide alternate assets for official builds.

BUG=chromium-os:5746,chromium-os:6321
TEST=booted it
TBR=cmasone

Review URL: http://codereview.chromium.org/3406006

Change-Id: Ia4c579a0ebe95c909332b2702f2ae3228798f221

joshfire/chromiumos-platform-init