swift: remove retrying code
swift: remove retrying code

This code became useless and bugged since we included LZ4 usage directly
into the Swift driver. It was meant to retry if the data from Swift was
null, not from lz4.loads().
So let's remove this.

Change-Id: I555d1366974ba599c63c8aa4ce316fd3e4e91253

leandroreox/gnocchi,gnocchixyz/gnocchi,leandroreox/gnocchi,sileht/gnocchi,gnocchixyz/gnocchi,sileht/gnocchi