avoid getting creds from environment during autoenable

When autoenabling special remotes of type S3, weddav, or glacier, do not
take login credentials from environment variables, as the user may not be
expecting the autoenable to happen, and may have those set for other
purposes.

Creds.hs

@@ -1,6 +1,6 @@
 {- Credentials storage
  -
- - Copyright 2012-2020 Joey Hess <id@joeyh.name>
+ - Copyright 2012-2021 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -25,6 +25,7 @@ import Annex.Common
 import qualified Annex
 import Types.Creds
 import Types.RemoteConfig
+import Types.Remote (SetupStage(..))
 import Annex.SpecialRemote.Config
 import Annex.Perms
 import Utility.FileMode
@@ -52,21 +53,25 @@ data CredPairStorage = CredPairStorage
  - that. Also caches them locally.
  -
  - The creds are found from the CredPairStorage storage if not provided,
- - so may be provided by an environment variable etc.
+ - so may be provided by an environment variable etc. When autoenabling,
+ - the user would not expect to provide creds, so none are found.
  -
  - The remote's configuration should have already had a cipher stored in it
  - if that's going to be done, so that the creds can be encrypted using the
  - cipher. The EncryptionIsSetup is witness to that being the case.
  -}
 setRemoteCredPair
-	:: EncryptionIsSetup
+	:: SetupStage
+	-> EncryptionIsSetup
 	-> ParsedRemoteConfig
 	-> RemoteGitConfig
 	-> CredPairStorage
 	-> Maybe CredPair
 	-> Annex RemoteConfig
-setRemoteCredPair encsetup pc gc storage mcreds = unparsedRemoteConfig <$>
-	setRemoteCredPair' pc encsetup gc storage mcreds
+setRemoteCredPair ss encsetup pc gc storage mcreds = case ss of
+	AutoEnable _ -> pure (unparsedRemoteConfig pc)
+	_ -> unparsedRemoteConfig <$>
+		setRemoteCredPair' pc encsetup gc storage mcreds
 
 setRemoteCredPair'
 	:: ParsedRemoteConfig