smaller delay in proxy streamer

A one second delay made it seem really choppy and slow when the special
remote was sending content fairly steadily but was bottlenecked on
running gpg on 10 mb chunks.

This does not appreciably increase CPU, although of course if the
special remote is very slow it will add up over time.

It would perhaps be better to use inotify, like tailVerify does.

Annex/Proxy.hs

@@ -28,16 +28,15 @@ import Logs.UUID
 import Logs.Location
 import Utility.Tmp.Dir
 import Utility.Metered
-import Utility.ThreadScheduler
 import Git.Types
 import qualified Database.Export as Export
 #ifndef mingw32_HOST_OS
 import Utility.OpenFile
 #endif
 
+import Control.Concurrent
 import Control.Concurrent.STM
 import Control.Concurrent.Async
-import Control.Concurrent.MVar
 import qualified Data.ByteString as B
 import qualified Data.ByteString as BS
 import qualified Data.ByteString.Lazy as L
@@ -300,7 +299,7 @@ proxySpecialRemote protoversion r ihdl ohdl owaitv oclosedv mexportdb = go
 			Right sz | sz > 0 && sz >= offset -> return ()
 			_ -> ifM (isEmptyMVar cancelv <&&> isEmptyMVar donev)
 				( do
-					threadDelaySeconds (Seconds 1)
+					threadDelay 40000
 					waitforfile
 				, do
 					return ()
@@ -317,7 +316,7 @@ proxySpecialRemote protoversion r ihdl ohdl owaitv oclosedv mexportdb = go
 					else do
 						-- Wait for more data to be
 						-- written to the file.
-						threadDelaySeconds (Seconds 1)
+						threadDelay 40000
 						getcontents n h
 				else if n' > 0
 					then do