Address feedback from glance-remote patch

This cleans up some of the quote and variable handling that was
pointed out in review of the previous patch. This is non-critical,
so I'm putting it in a subsequent patch to avoid disturbing the
careful alignment of patches across three projects that are mostly
approved.

Change-Id: I9b281efd74ba5cd78f97b84e5704b41fd040e481
diff --git a/lib/tempest b/lib/tempest
index 7e7f0ab..bbd23bb 100644
--- a/lib/tempest
+++ b/lib/tempest
@@ -353,8 +353,7 @@
     iniset $TEMPEST_CONFIG image-feature-enabled import_image $GLANCE_USE_IMPORT_WORKFLOW
     iniset $TEMPEST_CONFIG image-feature-enabled os_glance_reserved True
     if is_service_enabled g-api-r; then
-        iniset $TEMPEST_CONFIG image alternate_image_endpoint \
-               "image_remote"
+        iniset $TEMPEST_CONFIG image alternate_image_endpoint image_remote
     fi
 
     # Compute