[FS#95] system looses IPv6 prefix after valid_lft reaches 0

[LEDE Bugs]

The following task is now closed:

FS#95 - system looses IPv6 prefix after valid_lft reaches 0
User who did this - Jo-Philipp Wich (jow-)

Reason for closing: Fixed
Additional comments about closing: This should be fixed with the latest IPv6 stack updates. Please request a reopen if the issue still occurs.

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=95