frameworks: Fix javadoc error for SDK build

some of the internal frameworks core packages have
references to oss frameworks core packages.Droiddoc
is failing if these oss core packages are not
present in the path.This is causing SDB build
to fail. New variable VENDOR_FRAMEWORKS_CORE_JARS
is added to includes the needed oss frameworks
core jars. Adding the variable to modules causing
the sdk build issue fixes this.

CRs-fixed: 571837

Change-Id: I4cd70cc8fc161f841838a01491e6347e760b7f08