Fix fallout from r1609477.
Fix fallout from r1609477.

* build/run_tests.py
  (TestHarness.__init__): Don't assume that the base URL is set.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1609484 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion