Add parametric tests of Swift object API, part 2

Add positive tests of Swift object "GET" API from the viewpoint of
completeness of query parameters.

Change-Id: I3d4da9a8e431014cba5e96e01ea31ba4c7f54541
diff --git a/tempest/services/object_storage/object_client.py b/tempest/services/object_storage/object_client.py
index 53a3325..f3f4eb6 100644
--- a/tempest/services/object_storage/object_client.py
+++ b/tempest/services/object_storage/object_client.py
@@ -77,11 +77,16 @@
         resp, body = self.head(url)
         return resp, body
 
-    def get_object(self, container, object_name):
+    def get_object(self, container, object_name, metadata=None):
         """Retrieve object's data."""
 
+        headers = {}
+        if metadata:
+            for key in metadata:
+                headers[str(key)] = metadata[key]
+
         url = "{0}/{1}".format(container, object_name)
-        resp, body = self.get(url)
+        resp, body = self.get(url, headers=headers)
         return resp, body
 
     def copy_object_in_same_container(self, container, src_object_name,