netatalk: fix 64-bit build

The configure script sets LD_LIBRARY_PATH to the staging directory,
which makes the `ls` that is called in one of the tests fail. Fix by
not setting LD_LIBRARY_PATH when cross-compiling.

The patch has been sent upstream.

Also remove the BDB_LIB variable: it isn't used.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>