use own config for nexus7 instead of mangling ac100 bootimg files

debian/changelog

@@ -1,3 +1,11 @@
+livecd-rootfs (2.101) UNRELEASED; urgency=low
+
+  * instead of mangling the ac100 bootimg for nexus7 support, ship a proper
+    config in ac100-tarball-installer and build the nexus7 one from scratch
+    as well.
+
+ -- Oliver Grawert <ogra@ubuntu.com>  Tue, 20 Nov 2012 12:37:33 +0100
+
 livecd-rootfs (2.100) raring; urgency=low
 
   * clean up the userdata dir

live-build/auto/build

@@ -378,7 +378,8 @@ if [ "$SUBARCH" = "ac100" ] || [ "$SUBARCH" = "nexus7" ]; then
 
 	if [ "$SUBARCH" = "nexus7" ]; then
 		# adjust the bootimg cmdline parameters
-		Chroot chroot "abootimg -u /boot/installer-${KVERS}.img -c 'cmdline=root=/dev/mmcblk0p9 ro console=tty1 fbcon=rotate:1 quiet splash'"
+		rm -rf /boot/installer-${KVERS}.img
+		Chroot chroot "abootimg --create /boot/installer-${KVERS}.img -f /boot/bootimg.cfg-nexus7 -r /boot/initrd.img-${KVERS} -k /boot/vmlinuz-${KVERS}"
 
 		# roll the android rootfs images
 		mkdir -p userdata