#269 Make local_state_tree option not mandatory

Update and rename salt.html.markdown to salt-masterless.html.markdown
salt.html.markdown had a better history and formatting
And remove local_state_tree from required option from code and docs

provisioner/salt-masterless/provisioner.go

@@ -68,13 +68,12 @@ func (p *Provisioner) Prepare(raws ...interface{}) error {
 		}
 	}
 
-	if p.config.LocalStateTree == "" {
-		errs = packer.MultiErrorAppend(errs,
-			errors.New("Please specify a local_state_tree"))
-	} else if _, err := os.Stat(p.config.LocalStateTree); err != nil {
-		errs = packer.MultiErrorAppend(errs,
-			errors.New("local_state_tree must exist and be accessible"))
-	}
+	if p.config.LocalStateTree != "" {
+		if _, err := os.Stat(p.config.LocalStateTree); err != nil {
+			errs = packer.MultiErrorAppend(errs,
+				errors.New("local_state_tree must exist and be accessible"))
+		}
+        }
 
 	if errs != nil && len(errs.Errors) > 0 {
 		return errs

website/source/docs/provisioners/salt-masterless.html.markdown

@@ -24,14 +24,11 @@ The example below is fully functional.
 
 The reference of available configuration options is listed below. The only required argument is the path to your local salt state tree.
 
-Required:
+Optional:
 
 * `local_state_tree` (string) - The path to your local
   [state tree](http://docs.saltstack.com/ref/states/highstate.html#the-salt-state-tree).
-  This will be uploaded to the `/srv/salt` on the remote, and removed before
-  shutdown.
-
-Optional:
+  This will be uploaded to the `/srv/salt` on the remote.
 
 * `skip_bootstrap` (boolean) - By default the salt provisioner runs
   [salt bootstrap](https://github.com/saltstack/salt-bootstrap) to install