Expose IronicImageDownloadSource as a parameter

Setting this to "http" allows using the direct deploy interface
without Swift. It is particularly useful in the Edge case, as it
allows to download an image once to the conductor, and serve it
to all nodes within the location, without having Swift there.

Depends-On: https://review.openstack.org/#/c/601314/
Change-Id: Ifc6a809a45a2a08e5bb11f95b04ac4d69dada3c4

puppet/services/ironic-conductor.yaml

@@ -164,6 +164,12 @@ parameters:
     default: false
     description: Whether to enable use of staging drivers.
     type: boolean
+  IronicImageDownloadSource:
+    default: swift
+    description: Image delivery method for the "direct" deploy interface.
+                 Use "swift" for the Object Storage temporary URLs,
+                 use "http" for the local HTTP server (the same as for iPXE).
+    type: string
   IronicIPXEEnabled:
     default: true
     description: Whether to use iPXE instead of PXE for deployment.
@@ -299,6 +305,7 @@ outputs:
               - service_debug
               - 'always'
               - 'on_failure'
+            ironic::drivers::agent::image_download_source: {get_param: IronicImageDownloadSource}
             # NOTE(emilien): ILO defaulting to UEFI does not match other drivers so bios is used.
             ironic::drivers::ilo::default_boot_mode: 'bios'
             ironic::drivers::interfaces::enabled_bios_interfaces: {get_param: IronicEnabledBiosInterfaces}