in same cases it is required to avoid update all existing packages,
doing so can result in release update which is currently not possible
unless you not include "base" element.
"base" element used for most distribution (rhel, debain), and is
necessary for most cloud operations, this patch add
"DIB_AVOID_PACKAGES_UPDATE" parameter to skip updating all packages.
usecases for this patch can be:
* Avoid release update when building old release ex. RHEL7.5.
* build on network-less environment.
usage:
DIB_AVOID_PACKAGES_UPDATE=1
or
DIB_AVOID_PACKAGES_UPDATE=0
Change-Id: I71192b23c8f0bc48b348fe7377bf8a2399b53792
