checkrunner.py: make get_traceback return a string instead of list
@@ -231,7 +231,7 @@ def get_traceback():
render it. Run this inside of the except block.
"""
ex_type, ex, tb = sys.exc_info()
- result = traceback.format_tb(tb)
+ result = traceback.format_tb(tb)[0]
del tb
return result
