openflow: Improve PCAP capturing; change disconnect behavior
openflow: Improve PCAP capturing; change disconnect behavior

The PCAP capturing now puts every OpenFlow message in its own
pseudo-frame.  This way you can easily see all of them in
Wireshark.

Also, socket shutdown behavior should be improved (looks like
I had a longstanding little bug in there which was apparently
never a very big problem!).

MurphyMc/pox,kavitshah8/SDNDeveloper,andiwundsam/_of_normalize,waltznetworks/pox,waltznetworks/pox,pthien92/sdn,kulawczukmarcin/mypox,waltznetworks/pox,andiwundsam/_of_normalize,pthien92/sdn,kavitshah8/SDNDeveloper,kpengboy/pox-exercise,jacobq/csci5221-viro-project,VamsikrishnaNallabothu/pox,PrincetonUniversity/pox,carlye566/IoT-POX,PrincetonUniversity/pox,carlye566/IoT-POX,kulawczukmarcin/mypox,waltznetworks/pox,noxrepo/pox,pthien92/sdn,kulawczukmarcin/mypox,carlye566/IoT-POX,denovogroup/pox,diogommartins/pox,carlye566/IoT-POX,chenyuntc/pox,kpengboy/pox-exercise,MurphyMc/pox,jacobq/csci5221-viro-project,diogommartins/pox,chenyuntc/pox,denovogroup/pox,denovogroup/pox,denovogroup/pox,xAKLx/pox,jacobq/csci5221-viro-project,diogommartins/pox,VamsikrishnaNallabothu/pox,jacobq/csci5221-viro-project,xAKLx/pox,diogommartins/pox,VamsikrishnaNallabothu/pox,pthien92/sdn,kulawczukmarcin/mypox,denovogroup/pox,PrincetonUniversity/pox,adusia/pox,kulawczukmarcin/mypox,kpengboy/pox-exercise,VamsikrishnaNallabothu/pox,noxrepo/pox,adusia/pox,kavitshah8/SDNDeveloper,waltznetworks/pox,xAKLx/pox,noxrepo/pox,adusia/pox,kavitshah8/SDNDeveloper,adusia/pox,xAKLx/pox,VamsikrishnaNallabothu/pox,xAKLx/pox,chenyuntc/pox,PrincetonUniversity/pox,MurphyMc/pox,chenyuntc/pox,PrincetonUniversity/pox,noxrepo/pox,adusia/pox,kpengboy/pox-exercise,MurphyMc/pox,MurphyMc/pox,andiwundsam/_of_normalize,diogommartins/pox,chenyuntc/pox,carlye566/IoT-POX,jacobq/csci5221-viro-project,pthien92/sdn,andiwundsam/_of_normalize,kpengboy/pox-exercise