Rename object storage features section

In tempest/config.py this is defined as object-storage-feature-enabled.

Change-Id: I3149fbab908bb60cd570ee144ac2df8a3da25a23
diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index fc4f9cd..a79bfd3 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -309,7 +309,7 @@
 # Set operator role for tests that require creating a container
 operator_role = Member
 
-[object-feature-enabled]
+[object-storage-feature-enabled]
 # Set to True if the Account Quota middleware is enabled
 accounts_quotas = True
 # Set to True if the Container Quota middleware is enabled