Fix a Py2/3 incompatibility in profiler.
Fix a Py2/3 incompatibility in profiler.

robertwb/incubator-beam,lukecwik/incubator-beam,chamikaramj/beam,robertwb/incubator-beam,apache/beam,apache/beam,apache/beam,apache/beam,chamikaramj/beam,chamikaramj/beam,chamikaramj/beam,chamikaramj/beam,lukecwik/incubator-beam,chamikaramj/beam,robertwb/incubator-beam,iemejia/incubator-beam,robertwb/incubator-beam,robertwb/incubator-beam,apache/beam,lukecwik/incubator-beam,apache/beam,chamikaramj/beam,apache/beam,lukecwik/incubator-beam,robertwb/incubator-beam,iemejia/incubator-beam,lukecwik/incubator-beam,lukecwik/incubator-beam,lukecwik/incubator-beam,lukecwik/incubator-beam,chamikaramj/beam,apache/beam,robertwb/incubator-beam,chamikaramj/beam,apache/beam,robertwb/incubator-beam,apache/beam,robertwb/incubator-beam,apache/beam,robertwb/incubator-beam,lukecwik/incubator-beam,lukecwik/incubator-beam,chamikaramj/beam