trace: fix for python3
trace: fix for python3

xrange does not exist in py3.

iovisor/bcc,brendangregg/bcc,mcaleavya/bcc,iovisor/bcc,shodoco/bcc,brendangregg/bcc,shodoco/bcc,tuxology/bcc,romain-intel/bcc,iovisor/bcc,romain-intel/bcc,tuxology/bcc,shodoco/bcc,shodoco/bcc,shodoco/bcc,mcaleavya/bcc,mcaleavya/bcc,tuxology/bcc,mcaleavya/bcc,romain-intel/bcc,brendangregg/bcc,tuxology/bcc,iovisor/bcc,brendangregg/bcc,romain-intel/bcc,iovisor/bcc,brendangregg/bcc,tuxology/bcc,romain-intel/bcc,mcaleavya/bcc