virjsontest: use VIR_AUTOFREE for strings
virjsontest: use VIR_AUTOFREE for strings

The only remaining use of VIR_FREE is for reusing variables.

Signed-off-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

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