core: fix sysprep architecture values

arch values don't match the OS ini question - x86 instead of
amd64 for OSs which are 64 bit

Change-Id: Id61fea5f128de054bfe143d9888751205fa080e4
Bug-Url: https://bugzilla.redhat.com/1066884
Signed-off-by: Roy Golan <rgolan@redhat.com>
(cherry picked from commit b21e95affa4e0867ab675c1ffc733bfd35b761fb)