Have a way to disable Glance v1 in devstack

As part of the process of deprecating Glance's V1, the glance team would
like to start testing V2-only environments. Therefore, this change
provides a way to force other services to use V2.

Change-Id: I87e77d07964eac01e9a796817cbc88bd6e59c721
diff --git a/lib/glance b/lib/glance
index cda357f..2ad971f 100644
--- a/lib/glance
+++ b/lib/glance
@@ -57,6 +57,7 @@
 GLANCE_SWIFT_STORE_CONF=$GLANCE_CONF_DIR/glance-swift-store.conf
 GLANCE_GLARE_CONF=$GLANCE_CONF_DIR/glance-glare.conf
 GLANCE_GLARE_PASTE_INI=$GLANCE_CONF_DIR/glance-glare-paste.ini
+GLANCE_V1_ENABLED=${GLANCE_V1_ENABLED:-True}
 
 if is_ssl_enabled_service "glance" || is_service_enabled tls-proxy; then
     GLANCE_SERVICE_PROTOCOL="https"
@@ -134,6 +135,12 @@
         iniset $GLANCE_API_CONF DEFAULT disk_formats "ami,ari,aki,vhd,vmdk,raw,qcow2,vdi,iso,ploop"
     fi
 
+    # NOTE(flaper87): To uncomment as soon as all services consuming Glance are
+    # able to consume V2 entirely.
+    if [ "$GLANCE_V1_ENABLED" != "True" ]; then
+        iniset $GLANCE_API_CONF DEFAULT enable_v1_api False
+    fi
+
     # Store specific configs
     iniset $GLANCE_API_CONF glance_store filesystem_store_datadir $GLANCE_IMAGE_DIR/
     if is_service_enabled g-glare; then