[BUG] polycubed crashes when you try to delete a port of a router

[pinoOgni]

Describe the bug

Segmentation error when you try to delete a port in a router

In polycubectl

polycubectl add router r1
polycubectl r1 ports add p1
polycubectl r1 ports add p2
polycubectl r1 ports del p1
Delete http://localhost:9000/polycube/v1/router/r1/ports/p1/: EOF

In polycubed output

$ sudo polycubed loglevel=DEBUG
[2019-11-25 17:54:06.030] [polycubed] [info] loading configuration from /etc/polycube/polycubed.conf
[2019-11-25 17:54:06.031] [polycubed] [info] configuration parameters: 
[2019-11-25 17:54:06.031] [polycubed] [info]  loglevel: info
[2019-11-25 17:54:06.031] [polycubed] [info]  daemon: false
[2019-11-25 17:54:06.031] [polycubed] [info]  pidfile: /var/run/polycube.pid
[2019-11-25 17:54:06.031] [polycubed] [info]  port: 9000
[2019-11-25 17:54:06.031] [polycubed] [info]  addr: localhost
[2019-11-25 17:54:06.031] [polycubed] [info]  logfile: /var/log/polycube/polycubed.log
[2019-11-25 17:54:06.031] [polycubed] [info]  cubes-dump-file: /etc/polycube/cubes.yaml
[2019-11-25 17:54:06.031] [polycubed] [info]  cubes-dump-clean-init: false
[2019-11-25 17:54:06.031] [polycubed] [info]  cubes-dump-enable: false
[2019-11-25 17:54:06.031] [polycubed] [info] polycubed starting...
[2019-11-25 17:54:06.031] [polycubed] [info] version v0.1.0-beta+ [git: (branch/commit): master/ac19182e]
[2019-11-25 17:54:07.603] [polycubed] [info] rest server listening on '127.0.0.1:9000'
[2019-11-25 17:54:07.603] [polycubed] [info] rest server starting ...
[2019-11-25 17:54:07.621] [polycubed] [info] service bridge loaded using libpcn-bridge.so
[2019-11-25 17:54:07.628] [polycubed] [info] service ddosmitigator loaded using libpcn-ddosmitigator.so
[2019-11-25 17:54:07.639] [polycubed] [info] service firewall loaded using libpcn-firewall.so
[2019-11-25 17:54:07.646] [polycubed] [info] service helloworld loaded using libpcn-helloworld.so
[2019-11-25 17:54:07.673] [polycubed] [info] service k8switch loaded using libpcn-k8switch.so
[2019-11-25 17:54:07.680] [polycubed] [info] service k8sfilter loaded using libpcn-k8sfilter.so
[2019-11-25 17:54:07.716] [polycubed] [info] service lbdsr loaded using libpcn-lbdsr.so
[2019-11-25 17:54:07.744] [polycubed] [info] service lbrp loaded using libpcn-lbrp.so
[2019-11-25 17:54:07.773] [polycubed] [info] service nat loaded using libpcn-nat.so
[2019-11-25 17:54:07.810] [polycubed] [info] service pbforwarder loaded using libpcn-pbforwarder.so
[2019-11-25 17:54:07.847] [polycubed] [info] service router loaded using libpcn-router.so
[2019-11-25 17:54:07.865] [polycubed] [info] service simplebridge loaded using libpcn-simplebridge.so
[2019-11-25 17:54:07.872] [polycubed] [info] service simpleforwarder loaded using libpcn-simpleforwarder.so
[2019-11-25 17:54:07.884] [polycubed] [info] service iptables loaded using libpcn-iptables.so
[2019-11-25 17:54:07.890] [polycubed] [info] service transparenthelloworld loaded using libpcn-transparenthelloworld.so
[2019-11-25 17:54:07.896] [polycubed] [info] service synflood loaded using libpcn-synflood.so
[2019-11-25 17:54:07.933] [polycubed] [info] service packetcapture loaded using libpcn-packetcapture.so
[2019-11-25 17:54:12.570] [Router] [r1] [info] Creating Router instance
[2019-11-25 17:54:15.444] [Router] [r1] [info] Added new port: p1 (index: 0) [mac: d6:37:cb:ed:d3:8b - ip: ]
[2019-11-25 17:54:17.288] [Router] [r1] [info] Added new port: p2 (index: 1) [mac: 3e:13:41:13:7d:e2 - ip: ]
[2019-11-25 17:54:19.406] [Router] [r1] [info] Remove port p1
Errore di segmentazione

Expected behavior

Port deleted and not "segmentation error"

Please tell us about your environment:

polycube commit bd521f4
Ubuntu 18.04 5.0.0-36-generic