interceptor: record root dir in log

That is required to reconstruct the full working dir again later.
The root dir is either deducted from the environment ($ROOT_DIR) or is
cwd() of the interceptor process otherwise.

Bug: 205731786
Signed-off-by: Matthias Maennich <maennich@google.com>
Change-Id: I12d826d7459a83864ecd024d85c801f1011aee87
2 files changed