package/libs/libtool: rename to libltdl

package/libs/libtool: rename to libltdl

Source package libtool is used to package libltdl.
Unfortunately binary libtoolize is missing.
Packaging libtoolize would depend on package file which is in the
packages feed.
Felix Fietkau suggested to rename source libtool to libltdl
and to create a new package libtool in packages.

This patch contains the renaming.

CC: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@48149 3c298f89-4303-0410-b956-a3cf2f4a3e73