Comment 0 for bug 2006546

[Impact]
The arp_ndisc_evict_nocarrier.sh in selftests/net didn't pass a proper return value for failed test cases. Thus we might get false negatives if the last command runs successfully.

[Fix]
* 1856628baa selftests: net: return non-zero for failures reported in arp_ndisc_evict_nocarrier

This patch can be cherry-picked into affected kernels.

[Test]
Run the patched test, this should not cause any regression as sub tests are good with our kernels (except there is a cleanup issue in bug 1968310)
One can deliberately fail a test by hijacking the if statement for the return value check to make sure this patch is working as expected.

[Where problems could occur]
This patch improves the result interpretation, we might see new failures being reported.