Revert "build: require Jansson if QEMU driver is enabled"
Revert "build: require Jansson if QEMU driver is enabled"

This reverts commit 01ce04375c3348fd683475e5aa5231149ef6a78a.

Jansson cannot parse QEMU's quirky JSON.
Revert back to yajl.

https://bugzilla.redhat.com/show_bug.cgi?id=1614569

Signed-off-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>
Reviewed-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

nertpinx/libvirt,jfehlig/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,libvirt/libvirt,jfehlig/libvirt,crobinso/libvirt,libvirt/libvirt,jfehlig/libvirt,olafhering/libvirt,nertpinx/libvirt,jardasgit/libvirt,crobinso/libvirt,zippy2/libvirt,jfehlig/libvirt,crobinso/libvirt,eskultety/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,jardasgit/libvirt,jardasgit/libvirt,jardasgit/libvirt,eskultety/libvirt,olafhering/libvirt,zippy2/libvirt,libvirt/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,crobinso/libvirt,fabianfreyer/libvirt,libvirt/libvirt,zippy2/libvirt,andreabolognani/libvirt,nertpinx/libvirt,eskultety/libvirt,eskultety/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,olafhering/libvirt,eskultety/libvirt,andreabolognani/libvirt,zippy2/libvirt,olafhering/libvirt,andreabolognani/libvirt