Fix parsing of absolute job dependencies

It seems that Python code generates (sometimes) absolute job
dependencies which are strings, instead of integers, so we should be
able to parse these as well. We simply change from explicit int-based
parsing (makeJobId) to the generic one (parseJobId).

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Helga Velroyen <helgav@google.com>