Fix caching of decrypted ciphers, which failed when drop had to check multiple different encrypted special remotes.

Annex.hs

@@ -36,6 +36,7 @@ import Types.BranchState
 import Types.TrustLevel
 import Types.UUID
 import qualified Utility.Matcher
+import qualified Data.Map as M
 
 -- git-annex's monad
 newtype Annex a = Annex { runAnnex :: StateT AnnexState IO a }
@@ -70,7 +71,7 @@ data AnnexState = AnnexState
 	, limit :: Either [Utility.Matcher.Token (FilePath -> Annex Bool)] (Utility.Matcher.Matcher (FilePath -> Annex Bool))
 	, forcetrust :: [(UUID, TrustLevel)]
 	, trustmap :: Maybe TrustMap
-	, cipher :: Maybe Cipher
+	, ciphers :: M.Map EncryptedCipher Cipher
 	}
 
 newState :: Git.Repo -> AnnexState
@@ -93,7 +94,7 @@ newState gitrepo = AnnexState
 	, limit = Left []
 	, forcetrust = []
 	, trustmap = Nothing
-	, cipher = Nothing
+	, ciphers = M.empty
 	}
 
 {- Create and returns an Annex state object for the specified git repo. -}