dtls: contiki dtls_retransmit_process: remove node before transmit

Mimic the default 'dtls_check_retransmit' implementation.
The node should be popped before calling 'retransmit' and not freed after
transmit.

Change-Id: If1c11184e27025dc69c672588b946e3cf61054e1
Signed-off-by: Gaëtan Harter <gaetan.harter@inria.fr>
1 file changed