qemusecuritymock: Actually set error on failure
qemusecuritymock: Actually set error on failure

I don't really know what happened when I was writing the original
code, but even if error was to be set the corresponding boolean
was set to false meaning no error.

Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>
Reviewed-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

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