Both 'server' and 'dispatcher' roles need to check out openqa_
fedora_tools, but only 'dispatcher' needs to install it. To
avoid having to register a variable in 'server' too and have
the install task check if either variable |changed, just have
two separate checkouts, so the dispatcher checkout will always
have 'changed' when appropriate.
it seems variables in vars/main.yml are 'role variables' with
a high precedence, while variables in defaults/main.yml are
'role default variables' with a low precedence. This could be
made a hell of a lot clearer in the docs.
This adds openQA server, worker and dispatcher roles, and
applies them to the appropriate hosts. A few secret vars are
required. See trac #4958 for discussion.
