Install g-r version of OSC in configure_tempest

configure_tempest uses python-openstackclient (OSC) and we call
configure_tempest in grenade on the new side. So we need to make sure
the version of OSC is installed matches global-requirements on new.

Change-Id: I6fae9b8b081355b45e7c8d622d8db2482d41b464
Closes-Bug: #1454467
diff --git a/lib/tempest b/lib/tempest
index 6ce245a..1af5c7a 100644
--- a/lib/tempest
+++ b/lib/tempest
@@ -106,6 +106,10 @@
         pip_install_gr testrepository
     fi
 
+    # Used during configuration so make sure we have the correct
+    # version installed
+    pip_install_gr python-openstackclient
+
     local image_lines
     local images
     local num_images