Configurable volume storage_protocol + vendor_name

Allow storage_protocol and vendor name of configured backend
to be set in tempest.conf, allowing volume tests against drivers
other than the default (iSCSI).

Fixes bug #1194316

Change-Id: Ifd879d16e021b99e3d3d221e0bfea2f35e1a9767
diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index db6a7bd..8e0061f 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -229,6 +229,10 @@
 multi_backend_enabled = false
 backend1_name = BACKEND_1
 backend2_name = BACKEND_2
+# Protocol and vendor of volume backend to target when testing volume-types.
+# You should update to reflect those exported by configured backend driver.
+storage_protocol = iSCSI
+vendor_name = Open Source
 
 [object-storage]
 # This section contains configuration options used when executing tests