Zypper uses the concept of "vendor stickiness" and will refuse to
upgrade packages that require a vendor change. This change introduces
a new override variable to instruct zypper to view a list of vendors
as equivalent.
Change-Id: Ib3412b02f1edf9aae03cd5478ac2310cce3f2e8a
Signed-off-by: Nicolas Bock <nicolas.bock@suse.com>