Disable file injection for libvirt driver

Change-Id: I73289195d3bb455f4076fadd2eadd6036b04b722
diff --git a/lib/nova b/lib/nova
index d5f7514..0db242a 100644
--- a/lib/nova
+++ b/lib/nova
@@ -240,10 +240,9 @@
         sudo sysctl -w net.ipv4.ip_forward=1
 
         if [[ "$VIRT_DRIVER" = 'libvirt' ]]; then
-            # When libguestfs is available for file injection, enable using
-            # libguestfs to inspect the image and figure out the proper
-            # partition to inject into.
-            iniset $NOVA_CONF libvirt inject_partition '-1'
+            # File injection is being disabled by default in the near future -
+            # disable it here for now to avoid surprises later.
+            iniset $NOVA_CONF libvirt inject_partition '-2'
 
             # Check for kvm (hardware based virtualization).  If unable to initialize
             # kvm, we drop back to the slower emulation mode (qemu).  Note: many systems