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/Git.hs

@@ -136,7 +136,11 @@ gitSetup Init mu _ c _ = do
 	if isNothing mu || mu == Just u
 		then return (c, u)
 		else error "git remote did not have specified uuid"
-gitSetup (Enable _) (Just u) _ c _ = do
+gitSetup (Enable _) mu _ c _ = enableRemote mu c
+gitSetup (AutoEnable _) mu _ c _ = enableRemote mu c
+
+enableRemote :: Maybe UUID -> RemoteConfig -> Annex (RemoteConfig, UUID)
+enableRemote (Just u) c = do
 	inRepo $ Git.Command.run
 		[ Param "remote"
 		, Param "add"
@@ -144,7 +148,7 @@ gitSetup (Enable _) (Just u) _ c _ = do
 		, Param $ maybe (giveup "no location") fromProposedAccepted (M.lookup locationField c)
 		]
 	return (c, u)
-gitSetup (Enable _) Nothing _ _ _ = error "unable to enable git remote with no specified uuid"
+enableRemote Nothing _ = error "unable to enable git remote with no specified uuid"
 
 {- It's assumed to be cheap to read the config of non-URL remotes, so this is
  - done each time git-annex is run in a way that uses remotes, unless