Suricata

The IPPairGetIPPairFromHash() will increase the ippair->use_cnt by IPPairIncrUsecnt(). Other functions do the same.
But the IPPairDecrUsecnt() will be executed a few times less. This causes IPPair->use_cnt to never be 0. Eventually the memory runs out.

How to reproduce the problem:
1. Reduce the configured ：ippair.memcap;

2. tcpreplay a ftp.pcacp with --unique-ip opt;
3. AppLayerExpectationCreate() return error !!!

Please check the changes in version 5.0.3
https://github.com/OISF/suricata/compare/suricata-5.0.2...suricata-5.0.3