dpkg-native: Avoid 'file changed' errors from tar

Hardlink count duing do_package_write_deb can change causing dpkg-deb
failures. We don't care about this error case so avoid it by checking
the tar exit code.

[YOCTO #7529]

(From OE-Core rev: 8ee36a5f)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>