* Make the method `PatchPayload` send a patch with empty
payload patch if range's length is non-zero and if it's the
first call.
* Empty payload patches just cut original object payload. So, these
patches are also valid.
Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>
* The flag 'firstPayloadPatch' keeps its state after first
`PatchPayload` that make other calls incorrectly set patch
ranges.
Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>
