improve messages around export/import conflicts

A conflict can be caused by either export or import when the remote
supports both.

Annex/Export.hs

@@ -42,8 +42,12 @@ exportKey sha = mk <$> catKey sha
 		, keyChunkNum = Nothing
 		}
 
-warnExportConflict :: Remote -> Annex ()
-warnExportConflict r = toplevelWarning True $
-	"Export conflict detected. Different trees have been exported to " ++ 
-	Remote.name r ++ 
-	". Use git-annex export to resolve this conflict."
+warnExportImportConflict :: Remote -> Annex ()
+warnExportImportConflict r = do
+	ops <- Remote.isImportSupported r >>= return . \case
+		True -> "exported to and/or imported from"
+		False -> "exported to"
+	toplevelWarning True $
+		"Conflict detected. Different trees have been " ++ ops ++
+		Remote.name r ++ 
+		". Use git-annex export to resolve this conflict."

Command/Export.hs

@@ -156,7 +156,7 @@ changeExport r db new = do
 						startMoveFromTempName r db ek newf
 					_ -> stop
 		ts -> do
-			warning "Export conflict detected. Different trees have been exported to the same special remote. Resolving.."
+			warning "Resolving export conflict.."
 			forM_ ts $ \oldtreesha -> do
 				-- Unexport both the srcsha and the dstsha,
 				-- because the wrong content may have

Command/Sync.hs

@@ -755,7 +755,7 @@ seekExportContent o rs (currbranch, _) = or <$> forM rs go
 	fillexport _ _ [] _ = return False
 	fillexport r db (t:[]) mtbcommitsha = Command.Export.fillExport r db t mtbcommitsha
 	fillexport r _ _ _ = do
-		warnExportConflict r
+		warnExportImportConflict r
 		return False
 
 cleanupLocal :: CurrBranch -> CommandStart