Git can tell you what the root dir of the repo is, so the scripts don't
need to force the user to cd there first.
Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
If i tell you what branch i'm on, you tell me which debian archive
component to put the packages in. This feature is useful for automation
that builds emc2 and makes debian archives (buildbot, i'm looking at you).
We used to always use the branch name as the component name, for example
the v2.4_branch debs went into the v2.4_branch-{sim,rt} components.
This falls short if you want to do test builds of throw-away branches,
because the binary deb builders don't know the name of your branch, so
they don't know where to find the source debs. This commit puts all
unknown branches into a new component named "scratch", so the binary
deb builders' sources.list doesn't have to know all the branch names.
