tests: add warning that qemucapsprobe prefers native host/guest arch
tests: add warning that qemucapsprobe prefers native host/guest arch

Generally we want the QEMU capabilities data in git to report KVM
related features, and thus we strongly prefer that the capabilities are
generated on a native host.

Reviewed-by: Andrea Bolognani <3ada0bee826c753786fdbba72243dfba997094cf@redhat.com>
Signed-off-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

libvirt/libvirt,olafhering/libvirt,nertpinx/libvirt,olafhering/libvirt,olafhering/libvirt,nertpinx/libvirt,zippy2/libvirt,jfehlig/libvirt,crobinso/libvirt,libvirt/libvirt,jfehlig/libvirt,crobinso/libvirt,libvirt/libvirt,jfehlig/libvirt,zippy2/libvirt,libvirt/libvirt,crobinso/libvirt,jfehlig/libvirt,nertpinx/libvirt,olafhering/libvirt,nertpinx/libvirt,crobinso/libvirt,nertpinx/libvirt,zippy2/libvirt,zippy2/libvirt