Remove catch + sys.exit idiom

This is bad, python already prints exceptino message and exit with
non-zero code when an exception is raised, no need to catch the
exception just to print it. In addition, printing an exception does not
print stacktrace, so catch + sys.exit provide less information than
python's default behavior.

Test: th
Change-Id: If6cf2e34d4ebc9f7d172063b4396bf4377dad447