Sped up query commands that read the git-annex branch by around 5%

The only price paid is one additional MVar read per write to the journal.
Presumably writing a journal file dominiates over a MVar read time by
several orders of magnitude.

--batch does not get the speedup because then it needs to notice when
another process has made a change. Also made the assistant and other damon
modes bypass the optimisation, which would not help them anyway.

Command/TransferKeys.hs

@@ -17,6 +17,7 @@ import qualified Remote
 import Utility.SimpleProtocol (dupIoHandles)
 import Git.Types (RemoteName)
 import qualified Database.Keys
+import Annex.BranchState
 
 data TransferRequest = TransferRequest Direction Remote Key AssociatedFile
 
@@ -29,6 +30,7 @@ seek = withNothing (commandAction start)
 
 start :: CommandStart
 start = do
+	enableInteractiveJournalAccess
 	(readh, writeh) <- liftIO dupIoHandles
 	runRequests readh writeh runner
 	stop