The base syncd dockers follow a template, which defines the base docker as DOCKER_SYNCD_BASE instead of DOCKER_SYNCD_. Fix the docker-syncd-<mlnx, bfn>.mk to use the new one.
* [build]: put stretch debian packages under target/debs/stretch/
* in stretch build phase, all debian packages built in that stage are placed under target/debs/stretch directory.
* for python-based debian packages, since they are really the same for jessie and stretch, they are placed under target/python-debs directory.
Signed-off-by: Guohan Lu <gulv@microsoft.com>
