forge: fix random failures with testTemplateTool
getRepositoryList contain all business template repositories, ie:
['/srv/slapgrid/slappart4/srv/slapos/soft/c63ba7265399450b28f9ea6d5667a5e7/parts/erp5-doc/bt5', '/srv/slapgrid/slappart4/srv/slapos/soft/c63ba7265399450b28f9ea6d5667a5e7/parts/erp5/bt5', '/srv/slapgrid/slappart4/srv/slapos/soft/c63ba7265399450b28f9ea6d5667a5e7/parts/erp5/product/ERP5/bootstrap', '/srv/slapgrid/slappart4/srv/slapos/soft/c63ba7265399450b28f9ea6d5667a5e7/parts/erp5-bin/bt5']
it seems in random order.
Test was written to use the one from parts/erp5/bt5, but since it just takes "anything which does not contain bootstrap" it was sometimes getting erp5-bin or erp5-doc and could not find erp5_configurator_standard business template.
Change the selection of the repository to take into account that we may also have erp5-doc and erp5-bin and so that it fails if more than one.