NO-JIRA: HA fix hanging ha_tests.test_failover_send_receive on RHEL5

The test was hanging because of a python construct not available in 2.4.  It was
causing an exception in a strange place because this bit of code was imported at
runtime, and that was hanging the test. Fixed and did some cleanup
to avoid such mysterious hangs in future:

- Fixed qpidtoollibs/config.py to work with python 2.4.
- Import qpid-ha script at import time rather than runtime.
- Fix Popen.teardown logic to avoid hanging if a process can't be killed.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1591794 13f79535-47bb-0310-9956-ffa450edef68