libopenflow: Fix ofp_match lock/unlock
libopenflow: Fix ofp_match lock/unlock

Ouch.  Was doing a string comparison using "is", which worked on CPython
(which interned the strings), but not with PyPy.  Fixed.

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