Bug#352475: Does not generate modules.dep if no modules included on root floppy

[Frans Pop <aragorn@tiscali.nl>]

Here's the relevant bit of the build log for the root floppy that shows
what happens. As said before, there were no module udebs included in the
manifest for the root floppy.

<snip (with added newlines)>
# Set up modules.dep, ensure there is at least one standard dir (kernel
# in this case), so depmod will use its prune list for archs with no
# modules.
set -e; \
	sysmap_name=; sysmap_opt=; \
	if [ -n "" ]; then \
		[ ! -e ./tmp/powerpc_floppy_root/tree/boot/System.map-2.6.15-1-powerpc-miboot ] || \
		sysmap_name="./tmp/powerpc_floppy_root/tree/boot/System.map-2.6.15-1-powerpc-miboot"; \
	else \
		[ ! -e ./tmp/powerpc_floppy_root/tree/boot/System.map ] || \
		sysmap_name="./tmp/powerpc_floppy_root/tree/boot/System.map"; \
	fi; \
	[ -z "$sysmap_name" ] || sysmap_opt="-F $sysmap_name"; \
	if [ -d ./tmp/powerpc_floppy_root/tree/lib/modules/2.6.15-1-powerpc-miboot ]; then
		mkdir -p ./tmp/powerpc_floppy_root/tree/lib/modules/2.6.15-1-powerpc-miboot/kernel; \
		depmod $sysmap_opt -q -a -b ./tmp/powerpc_floppy_root/tree/ 2.6.15-1-powerpc-miboot; \
	fi; \
	[ -z "$sysmap_name" ] || mv $sysmap_name ./tmp/powerpc_floppy_root;
# These files depmod makes are used by hotplug, if it's being used;
# otherwise, we shouldn't need them. Some files aren't even used by
# hotplug, so never include them.
if [ -d ./tmp/powerpc_floppy_root/tree/etc/udev ] || [ -d ./tmp/powerpc_floppy_root/tree/etc/hotplug ]; then \
		find ./tmp/powerpc_floppy_root/tree/lib/modules/ -name 'modules*' \
			-not -name modules.dep -not -name modules.alias \
			-not -name 'modules.*map' \
			-not -type d | xargs rm -f; \
	else \
		find ./tmp/powerpc_floppy_root/tree/lib/modules/ -name 'modules*' \
			-not -name modules.dep -not -type d | xargs rm -f; \
	fi
find: ./tmp/powerpc_floppy_root/tree/lib/modules/: No such file or directory
</snip>