Unused variables in _PropertyMixin.update method

[HemangChothani]

Here is the method definition:

python-storage/google/cloud/storage/_helpers.py

Lines 311 to 318 in 792b21f

	def update(
	self,
	client=None,
	timeout=_DEFAULT_TIMEOUT,
	if_generation_match=None,
	if_generation_not_match=None,
	if_metageneration_match=None,
	if_metageneration_not_match=None,

In the implementation if_generation_match and if_generation_not_match are missing.

python-storage/google/cloud/storage/_helpers.py

Lines 363 to 366 in 792b21f

	_add_generation_match_parameters(
	query_params,
	if_metageneration_match=if_metageneration_match,
	if_metageneration_not_match=if_metageneration_not_match,

./cc @frankyn

[frankyn]

@IlyaFaer, looks like I missed this during review. Thanks @HemangChothani for the catch!

[IlyaFaer]

@frankyn, well, we all missed it. In docs we have only two metageneration* args for Bucket.update() and all four args for Blob.update(). Both are delegating to _PropertyMixin.update(). First I've added meta* for Bucket.update(). And then two others for Blob.update(), but forgot to add them into _add_generation_match_parameters() call.