switch from hslogger to purpose-built Utility.Debug

This uses a DebugSelector, rather than debug levels, which will allow
for a later option like --debug-from=Process to only
see debuging about running processes.

The module name that contains the thing being debugged is used as the
DebugSelector (in most cases; does not need to be a hard and fast rule).
Debug calls were changed to add that. hslogger did not display
that first parameter to debugM, but the DebugSelector does get
displayed.

Also fastDebug will allow doing debugging in places that are used in
tight loops, with the DebugSelector coming from the Annex Reader
essentially for free. Not done yet.

P2P/IO.hs

@@ -5,7 +5,7 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
-{-# LANGUAGE RankNTypes, FlexibleContexts, CPP #-}
+{-# LANGUAGE RankNTypes, FlexibleContexts, OverloadedStrings, CPP #-}
 
 module P2P.IO
 	( RunProto
@@ -35,6 +35,7 @@ import Utility.SimpleProtocol
 import Utility.Metered
 import Utility.Tor
 import Utility.FileMode
+import Utility.Debug
 import Types.UUID
 import Annex.ChangedRefs
 import qualified Utility.RawFilePath as R
@@ -48,7 +49,6 @@ import Control.Concurrent.Async
 import Control.Concurrent.STM
 import qualified Data.ByteString as B
 import qualified Data.ByteString.Lazy as L
-import System.Log.Logger (debugM)
 import qualified Network.Socket as S
 
 -- Type of interpreters of the Proto free monad.
@@ -235,7 +235,7 @@ runNet runst conn runner f = case f of
 debugMessage :: P2PConnection -> String -> Message -> IO ()
 debugMessage conn prefix m = do
 	tid <- myThreadId	
-	debugM "p2p" $ concat $ catMaybes $
+	debug "P2P.IO" $ concat $ catMaybes $
 		[ (\ident -> "[" ++ ident ++ "] ") <$> mident
 		, Just $ "[" ++ show tid ++ "] "
 		, Just $ prefix ++ " " ++ unwords (formatMessage safem)