[openstack|compute] Added request for boot_from_snapshot.

lib/fog/openstack/compute.rb

@@ -66,6 +66,7 @@ module Fog
       request :add_fixed_ip
       request :remove_fixed_ip
       request :server_diagnostics
+      request :boot_from_snapshot
 
       # Server Extenstions
       request :get_console_output

lib/fog/openstack/requests/compute/boot_from_snapshot.rb

@@ -0,0 +1,40 @@
+module Fog
+  module Compute
+    class OpenStack
+      class Real
+        def boot_from_snapshot(name, image_ref, flavor_ref, options={})
+          data = {
+            'server' => {
+              'flavorRef'  => flavor_ref,
+              'imageRef'   => image_ref,
+              'name'       => name
+            }
+          }
+
+          vanilla_options = ['metadata', 'accessIPv4', 'accessIPv6',
+                             'availability_zone', 'user_data', 'block_device_mapping']
+          vanilla_options.select{|o| options[o]}.each do |key|
+            data['server'][key] = options[key]
+          end
+
+          if options['personality']
+            data['server']['personality'] = []
+            for file in options['personality']
+              data['server']['personality'] << {
+                'contents'  => Base64.encode64(file['contents']),
+                'path'      => file['path']
+              }
+            end
+          end
+
+          request(
+            :body     => MultiJson.encode(data),
+            :expects  => [200, 202],
+            :method   => 'POST',
+            :path     => '/os-volumes_boot.json'
+          )
+        end
+      end
+    end # class OpenStack
+  end # module Compute
+end # module Fog