qemu: Return -EINVAL to keep qemuDomainOpenFile() consistent
qemu: Return -EINVAL to keep qemuDomainOpenFile() consistent

The description of the function says that the return value is a
file descriptor on success and negative errno on failure which is
not true. If the 'if' case with check on security labels fails,
the return value is -1 not -errno. The solution is to return
'-EINVAL' instead.

Signed-off-by: Kristina Hanicova <e70d889c982bbe3b9ce2841af457ca911bff1baa@redhat.com>
Reviewed-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>

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