add startingNoMessage

Fixes the last wart in the StartMessage transition. A few commands
include other CommandStart actions that generate output, and
do not themselves need to display a start/end message.

Command.hs

@@ -1,6 +1,6 @@
 {- git-annex command infrastructure
  -
- - Copyright 2010-2016 Joey Hess <id@joeyh.name>
+ - Copyright 2010-2019 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -82,6 +82,11 @@ starting msg t a = next (StartMessage msg (mkActionItem t), a)
 startingUsualMessages :: MkActionItem t => String -> t -> CommandPerform -> CommandStart
 startingUsualMessages msg t a = next (StartUsualMessages msg (mkActionItem t), a)
 
+{- When no message should be displayed at start/end, but messages can still 
+ - be displayed when using eg includeCommandAction. -}
+startingNoMessage :: MkActionItem t => t -> CommandPerform -> CommandStart
+startingNoMessage t a = next (StartNoMessage (mkActionItem t), a)
+
 {- For commands that do not display usual start or end messages, 
  - but have some other custom output. -}
 startingCustomOutput :: MkActionItem t => t -> CommandPerform -> CommandStart