fix transferring to gcrypt repo from direct mode repo

recvkey was told it was receiving a HMAC key from a direct mode repo,
and that confused it into rejecting the transfer, since it has no way to
verify a key using that backend, since there is no HMAC backend.

I considered making recvkey skip verification in the case of an unknown
backend. However, that could lead to bad results; a key can legitimately be
in the annex with a backend that the remote git-annex-shell doesn't know
about. Better to keep it rejecting if it cannot verify.

Instead, made the gcrypt special remote not set the direct mode flag when
sending (and receiving) files.

Also, added some recvkey messages when its checks fail, since otherwise
all that is shown is a confusing error message from rsync when the remote
git-annex-shell exits nonzero.

Remote/Helper/Ssh.hs

@@ -19,7 +19,6 @@ import Types.Key
 import Remote.Helper.Messages
 import Utility.Metered
 import Utility.Rsync
-import Config
 import Types.Remote
 import Logs.Transfer
 
@@ -111,10 +110,9 @@ rsyncHelper callback params = do
 
 {- Generates rsync parameters that ssh to the remote and asks it
  - to either receive or send the key's content. -}
-rsyncParamsRemote :: Remote -> Direction -> Key -> FilePath -> AssociatedFile -> Annex [CommandParam]
-rsyncParamsRemote r direction key file afile = do
+rsyncParamsRemote :: Bool -> Remote -> Direction -> Key -> FilePath -> AssociatedFile -> Annex [CommandParam]
+rsyncParamsRemote direct r direction key file afile = do
 	u <- getUUID
-	direct <- isDirect
 	let fields = (Fields.remoteUUID, fromUUID u)
 		: (Fields.direct, if direct then "1" else "")
 		: maybe [] (\f -> [(Fields.associatedFile, f)]) afile