Keep polling for IPv6 address on EADDRNOTAVAIL

When the interface has no IPv6 address yet, the error is EADDRNOTAVAIL,
not ENETUNREACH.

Bug: 272147547
Bug: 272917228
Bug: 272925668
Test: atest
Change-Id: I189f691405e2e0596ea0c9fe8f8ffe3c21dd5b46
1 file changed