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.

Remote/GitLFS.hs

@@ -150,6 +150,7 @@ mySetup ss mu _ c gc = do
 	let failinitunlessforced msg = case ss of
 		Init -> unlessM (Annex.getState Annex.force) (giveup msg)
 		Enable _ -> noop
+		AutoEnable _ -> noop
 	case (isEncrypted pc, Git.GCrypt.urlPrefix `isPrefixOf` url) of
 		(False, False) -> noop
 		(True, True) -> Remote.GCrypt.setGcryptEncryption pc remotename