Don't use non-zero exit code for test-crawler runs with nonvalidating html warnings.

 - Legacy-Id: 9559

Author: levkowetz

bin/test-crawl

@@ -273,6 +273,6 @@ if __name__ == "__main__":
         sys.stderr.write("Found no errors.")
     if warnings > 0:
         sys.stderr.write("Found %s warnings, grep output for WARN for details\n" % warnings)
-        sys.exit(1)
+        sys.exit(0)
     else:
         sys.stderr.write("Found no warnings.")