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

gnocchi/storage/swift.py

@@ -21,7 +21,6 @@ import uuid
 import lz4
 from oslo_config import cfg
 from oslo_log import log
-import retrying
 import six
 from six.moves.urllib.parse import quote
 try:
@@ -69,10 +68,6 @@ OPTS = [
 ]
 
 
-def retry_if_result_empty(result):
-    return len(result) == 0
-
-
 class SwiftStorage(_carbonara.CarbonaraBasedStorage):
 
     WRITE_FULL = True
@@ -228,9 +223,6 @@ class SwiftStorage(_carbonara.CarbonaraBasedStorage):
                     # Deleted in the meantime? Whatever.
                     raise
 
-    @retrying.retry(stop_max_attempt_number=4,
-                    wait_fixed=500,
-                    retry_on_result=retry_if_result_empty)
     def _get_measures(self, metric, timestamp_key, aggregation, granularity,
                       version=3):
         try:
@@ -271,9 +263,6 @@ class SwiftStorage(_carbonara.CarbonaraBasedStorage):
                 continue
         return keys
 
-    @retrying.retry(stop_max_attempt_number=4,
-                    wait_fixed=500,
-                    retry_on_result=retry_if_result_empty)
     def _get_unaggregated_timeserie(self, metric):
         try:
             headers, contents = self.swift.get_object(