docs/manual/configure.adoc: fix location of Busybox inittab

Commit 89d39fc7a392 "initscripts: new package" moved the inittab
packaged for Busybox init from system/skeleton/etc to package/busybox.
The manual, however, still points to the old location, so let's fix it.

Signed-off-by: Edgar Bonet <bonet@grenoble.cnrs.fr>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

docs/manual/configure.adoc

@@ -399,7 +399,7 @@ can be chosen from +System configuration+, +Init system+:
    BusyBox +inittab+ syntax is special: do not use a random +inittab+
    documentation from the Internet to learn about BusyBox
    +inittab+). The default +inittab+ in Buildroot is stored in
-   +system/skeleton/etc/inittab+. Apart from mounting a few important
+   +package/busybox/inittab+. Apart from mounting a few important
    filesystems, the main job the default inittab does is to start the
    +/etc/init.d/rcS+ shell script, and start a +getty+ program (which
    provides a login prompt).