FIX: Don't seed flags if ids don't exist

This can happen if you use the `replace_flags` plugin API to remove
a flag.

db/fixtures/003_post_action_types.rb

@@ -13,37 +13,47 @@ PostActionType.seed do |s|
   s.position = 2
 end
 
-PostActionType.seed do |s|
-  s.id = PostActionType.types[:off_topic]
-  s.name_key = 'off_topic'
-  s.is_flag = true
-  s.position = 3
+if PostActionType.types[:off_topic]
+  PostActionType.seed do |s|
+    s.id = PostActionType.types[:off_topic]
+    s.name_key = 'off_topic'
+    s.is_flag = true
+    s.position = 3
+  end
 end
 
-PostActionType.seed do |s|
-  s.id = PostActionType.types[:inappropriate]
-  s.name_key = 'inappropriate'
-  s.is_flag = true
-  s.position = 4
+if PostActionType.types[:inappropriate]
+  PostActionType.seed do |s|
+    s.id = PostActionType.types[:inappropriate]
+    s.name_key = 'inappropriate'
+    s.is_flag = true
+    s.position = 4
+  end
 end
 
-PostActionType.seed do |s|
-  s.id = PostActionType.types[:spam]
-  s.name_key = 'spam'
-  s.is_flag = true
-  s.position = 6
+if PostActionType.types[:spam]
+  PostActionType.seed do |s|
+    s.id = PostActionType.types[:spam]
+    s.name_key = 'spam'
+    s.is_flag = true
+    s.position = 6
+  end
 end
 
-PostActionType.seed do |s|
-  s.id = PostActionType.types[:notify_user]
-  s.name_key = 'notify_user'
-  s.is_flag = true
-  s.position = 7
+if PostActionType.types[:notify_user]
+  PostActionType.seed do |s|
+    s.id = PostActionType.types[:notify_user]
+    s.name_key = 'notify_user'
+    s.is_flag = true
+    s.position = 7
+  end
 end
 
-PostActionType.seed do |s|
-  s.id = PostActionType.types[:notify_moderators]
-  s.name_key = 'notify_moderators'
-  s.is_flag = true
-  s.position = 8
+if PostActionType.types[:notify_moderators]
+  PostActionType.seed do |s|
+    s.id = PostActionType.types[:notify_moderators]
+    s.name_key = 'notify_moderators'
+    s.is_flag = true
+    s.position = 8
+  end
 end