packet: Fix TCP flags (SYN, RST, etc.)
packet: Fix TCP flags (SYN, RST, etc.)

These were recently added, and while the getters were implemented right,
the setters were not.  Fixed.

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