This allows to Specify a random sleep time (with 'sleep' parameter) to
get more realistic results. Update the example accordingly.

Avoid concatenation of None and string vlaues if profile_path is defined later in vcs_repository_list.

refactor code to be possible pass the parameter bt5_path to runTestSuite. With this, runTestSuite script can propagate this parameter to runUnitTest script

Also, allow to check the transition message after the dialog to make sure, and
retry if the check fails and the maximum number of attempts is not 1.

This way, it is possible to confirm an object and check that it has been
confirmed in only one call including retries.

It was involving twisted conversion back and forth between
erp5.util.testbrowser which expected the URL and ERP5 site id whereas
erp5.util.benchmark which only expected the full URL.

Moreover, it was not working if there is no "real" ERP5 site ID, for example
with: http://foobar.org/.

Clear the Browser history (storing (request, response)) after each
suite. Moreover, it does make sense to keep it as suites are independent of
each other.

Before, if the first iteration failed, the whole execution failed even if the
number of maximum errors specified on the command line argument was not
reached, which was an issue especially when running with a range of users.

The results are now adjusted dynamically after the first successful iteration
rather than at the first iteration.

It should be set according the number of repeats and benchmark suites if the
number of errors is greater to report errors properly to the control process.

Using the same IP address may produce unrealistic results, thus allow to set
the source IP address (only meaningful when not using SlapOS). Network alias
interfaces must be set up before running the script.