Add run tests as thin provisioning

Some vendors might not have enough available space for testing features
that require creating huge volumes. So, this patch adds a new tempest
CONF `capability_thin_provisioned` that could be used to create volumes
as thin provisioned during the test execution.

Change-Id: I646f782c3e2be5ac799254f08a248a22cb9e0358
diff --git a/manila_tempest_tests/tests/api/base.py b/manila_tempest_tests/tests/api/base.py
index 0e875c2..dd25062 100755
--- a/manila_tempest_tests/tests/api/base.py
+++ b/manila_tempest_tests/tests/api/base.py
@@ -1081,6 +1081,8 @@
         extra_specs_dict = {"driver_handles_share_servers": dhss}
         if extra_specs:
             extra_specs_dict.update(extra_specs)
+        if CONF.share.capability_thin_provisioned:
+            extra_specs_dict['thin_provisioning'] = 'True'
         return extra_specs_dict
 
     @classmethod