ematch: Fix early ending of inverted containers.

The result of a negated container has to be inverted before checking for
early ending.

This fixes my previous attempt (17c9c823) to
make inverted containers work correctly.

Signed-off-by: Ignacy Gawędzki <ignacy.gawedzki@green-communications.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>