Fix assignment of comparison against zero

Fix assignment of comparison against zero

Assign the value we're comparing:
(val = func()) < 0
instead of assigning the comparison value:
(val = func() < 0)

Both were introduced along with the code,
the TLS tests by commit bd789df in 0.9.4
net events by commit de87691 in 1.2.2.

Note that the event id type fix is a no-op:
vshNetworkEventIdTypeFromString can only return
-1 (failure) and the event is never used or
0 (the only possible event) and the value of 0 < 0 is still 0.