Salt Provisioner: Added a 'custom' option to install_type to allow mo…

…re flexibility in passing arguments to the bootstrap script. Updated the docs.

plugins/provisioners/salt/provisioner.rb

@@ -135,7 +135,11 @@ def bootstrap_options(install, configure, config_dir)
         end
 
         if @config.install_type
-          options = "%s %s" % [options, @config.install_type]
+          # Allow passing install_args as an arbitrary string rather
+          # than trying to format it based on known options
+          if @config.install_type != "custom"
+            options = "%s %s" % [options, @config.install_type]
+          end
         end
 
         if @config.install_args

website/docs/source/v2/provisioning/salt.html.md

@@ -55,17 +55,20 @@ on this machine. Not supported on Windows.
 * `install_syndic`   (boolean) - Install the salt-syndic, default
 `false`. Not supported on Windows.
 
-* `install_type`  (stable | git | daily | testing) - Whether to install from a
+* `install_type`  (stable | git | daily | testing | custom) - Whether to install from a
 distribution's stable package manager, git tree-ish, daily ppa, or testing repository.
+The custom type allows passing an arbitrary string of arguments via `install_args`
+rather than formatting the arguments based on known install types.
 Not supported on Windows.
 
 * `install_args` (develop) - When performing a git install,
-you can specify a branch, tag, or any treeish. Not supported on Windows.
+you can specify a branch, tag, or any treeish. If using the `custom` install type,
+you can also specify a different repository to install from.
+Not supported on Windows.
 
 * `always_install`   (boolean) - Installs salt binaries even
  if they are already detected, default `false`
 
-
 * `bootstrap_options` (string) - Additional command-line options to
   pass to the bootstrap script.