The modern hwdb.bin format contains the filenames of the input data that
makes up the database. This is useful but in offline builds where
--root is used, the filenames are the full build paths including the
specified root. This introduces build paths and thus information
leakage and non-reproducible data.
Solve this by stripping the root prefix off the original path when
passing to import_file.
Add TEST-17-UDEV.hwdb.sh to verify that hwdb.bin files contain the
path inside the root, but not the path of the root.
Ross Burton
ab9be70e94