The trace-summary script is installed with a hashbang line of
"/usr/bin/env python", which will fail on most OS with only Python 3
(i.e., no Python 2 installed). The fix for this is to let cmake substitute
in the full path to the python interpreter (this is how broctl is installed).
Branch "topic/dnthayer/ticket1749" in the trace-summary repo contains the fix
for this issue.