shadow: Fix various invalid assumptions about directory layout

shadow: Fix various invalid assumptions about directory layout

The makefiles in the shadow package have their own hard-coded paths
for ${base_bindir} and ${base_sbindir} (known as "bindir" and "sbindir"
in shadow-speak).  Ensure that they install into our paths rather than
their own.

Also check that ${base_bindir} and ${bindir} are different before trying
to move files from one to the other; likewise for ${base_sbindir} and
${sbindir}.

(From OE-Core rev: d4e62e164ef73b47c178edcbc2579f5358934afc)

Signed-off-by: Phil Blundell <pb@pbcl.net>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>