tgz files in trials can be categorized in subdirectories, allowing to
select different bianry files at runtime based on the target run node
which is going to run them. This way for instance one can have a binary
linked against libs for eg. CentOS under run_label "centos/" or an ARM
target under "arm", and then use "run_label: arm" on the resource using
it.
Change-Id: Iaf2e97da3aff693395f44f0e93b184d4846cf6da
Pau Espin