Backport patches for Bloodhound commit ticket updater component

[Olemis Lang <olemis+trac@…>]

While implementing Bloodhound multi-product version of the commit ticket updater component​ we have produced some patches suitable to be backported into Trac . These are :

• portions of ​https://issues.apache.org/bloodhound/attachment/ticket/695/t695_r1534486_commit_ticket_update.tests.func.diff implementing functional test cases for this feature.
  • extend the signature of functional test env's svn_* methods.
• ​t695_r1545950_twill_write_html.diff which is aimed at logging failure conditions for test case classes defining local setUp and tearDown methods, like those included in patch mentioned above and in ​XmlRpcPlugin test suite.

Functional test case classes in Trac test suite mostly execute runTest method , nevertheless RPC test cases as well as those proposed in the patches use a class-level fixture initialization i.e. test_* methods wrapped in setUp and tearDown . Should many of these fail while executing a test run then twill output a single log file because the class name is the same for all instances and subsequent generations will be overwritten . That's what the later patch is all about .