core.link: free any packets left in link when freeing link
core.link: free any packets left in link when freeing link

Due to how the engine works, the case that a link is non-empty between
breaths is rare (specifically, it should only occur when an app pushes
to a “slow” output interface). That’s probably why this went unnoticed
until now. I don’t even have a case that triggers this bug, it just came
to me.

snabbco/snabb,snabbco/snabb,SnabbCo/snabbswitch,eugeneia/snabbswitch,eugeneia/snabb,dpino/snabbswitch,alexandergall/snabbswitch,SnabbCo/snabbswitch,dpino/snabb,alexandergall/snabbswitch,alexandergall/snabbswitch,Igalia/snabbswitch,snabbco/snabb,eugeneia/snabb,dpino/snabb,Igalia/snabbswitch,dpino/snabb,eugeneia/snabb,Igalia/snabb,dpino/snabbswitch,Igalia/snabb,snabbco/snabb,Igalia/snabb,dpino/snabbswitch,eugeneia/snabb,snabbco/snabb,alexandergall/snabbswitch,Igalia/snabbswitch,eugeneia/snabbswitch,dpino/snabb,snabbco/snabb,Igalia/snabb,SnabbCo/snabbswitch,dpino/snabb,alexandergall/snabbswitch,Igalia/snabb,alexandergall/snabbswitch,eugeneia/snabbswitch,snabbco/snabb,SnabbCo/snabbswitch,eugeneia/snabb,dpino/snabbswitch,dpino/snabb,eugeneia/snabb,eugeneia/snabb,Igalia/snabb,alexandergall/snabbswitch,Igalia/snabbswitch,eugeneia/snabb,Igalia/snabb,snabbco/snabb,eugeneia/snabbswitch,Igalia/snabb,Igalia/snabbswitch,dpino/snabb,alexandergall/snabbswitch