inetutils: disable rpath

The rpath, which configuration computers, is a host-related path in
cross-compile environment; In fact, need to not add rpath into elf
file.

   WARNING: QA Issue: package inetutils-ftp contains bad RPATH
   /buildarea/build/new/bitbake_build/tmp/sysroots/qemux86-64/usr/lib64 in file
   /buildarea/build/new/bitbake_build/tmp/work/x86_64-wrs-linux/inetutils/1.9.1-r1/packages-split/inetutils-ftp/usr/bin/ftp.inetutils

Signed-off-by: Roy Li <rongqing.li@windriver.com>
Reviewed-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Joe MacDonald <joe@deserted.net>