Add x-amz-storage-class support (#5295)

This adds configurable data and parity options on a per object
basis. To use variable parity

- Users can set environment variables to cofigure variable
parity

- Then add header x-amz-storage-class to putobject requests
with relevant storage class values

Fixes #4997

cmd/object-api-multipart_test.go

@@ -238,7 +238,8 @@ func testPutObjectPartDiskNotFound(obj ObjectLayer, instanceType string, disks [
 	if err == nil {
 		t.Fatalf("Test %s: expected to fail but passed instead", instanceType)
 	}
-	expectedErr := InsufficientWriteQuorum{}
+	// as majority of xl.json are not available, we expect InsufficientReadQuorum while trying to fetch the object quorum
+	expectedErr := InsufficientReadQuorum{}
 	if err.Error() != expectedErr.Error() {
 		t.Fatalf("Test %s: expected error %s, got %s instead.", instanceType, expectedErr, err)
 	}