DO NOT MERGE Pass source's info_dict to vendor's releasetools.py.

When building incremental packages, the info_dict from the source build
should be the one in use. We have done that for most of the partitions
(system and etc.), and should pass that to vendor's script as well.

Also includes the CL in commit aac4ad56
that fixes a bug in commit 6f0b219a.

Bug: 24898607
Change-Id: I4ea6037dad7061e1683661fc4c394fa3a7a7c5cd
(cherry picked from commit 6f0b219a)