Update lib/ironic to always skip cleaning

Previously, devstack would disable ironic's cleaning phase if a driver
with "agent" in the name was used. However, we have begun using the IPA
ramdisk for all tests in the gate, which caused cleaning to be run for
the "pxe_ssh" job which therefore fails due to timeouts.

As a result, for now, we need to always disable cleaning.

As a point of record, we should actually be testing cleaning in the
gate. However, running 'shred' on the disks of a nested VM is too slow
and causes the gate to timeout // take too long. Some options have been
discussed for ways to test the callback mechanism but avoid actually
running 'shred' on the disks.

This needs to be revisited.

Change-Id: Id15cf6cc49122b08e557e44871b31a8c0d20b55d
Related-to-Bug: #1517277
diff --git a/lib/ironic b/lib/ironic
index 27b0c8d..2fb2004 100644
--- a/lib/ironic
+++ b/lib/ironic
@@ -365,6 +365,9 @@
         iniset $IRONIC_CONF_FILE pxe pxe_append_params "$pxe_params"
     fi
 
+    # Set these options for scenarios in which the agent fetches the image
+    # directly from glance, and don't set them where the image is pushed
+    # over iSCSI.
     if is_deployed_by_agent; then
         if [[ "$SWIFT_ENABLE_TEMPURLS" == "True" ]] ; then
             iniset $IRONIC_CONF_FILE glance swift_temp_url_key $SWIFT_TEMPURL_KEY
@@ -379,9 +382,13 @@
         iniset $IRONIC_CONF_FILE glance swift_container glance
         iniset $IRONIC_CONF_FILE glance swift_temp_url_duration 3600
         iniset $IRONIC_CONF_FILE agent heartbeat_timeout 30
-        iniset $IRONIC_CONF_FILE agent agent_erase_devices_priority 0
     fi
 
+    # FIXME: this really needs to be tested in the gate.
+    # For now, any test using the agent ramdisk should skip cleaning
+    # because it is too slow to run in the gate.
+    iniset $IRONIC_CONF_FILE agent agent_erase_devices_priority 0
+
     if [[ "$IRONIC_IPXE_ENABLED" == "True" ]] ; then
         local pxebin
         pxebin=`basename $IRONIC_PXE_BOOT_IMAGE`