fix unknown total progress

- depends on tqdm/tqdm#800

dvc/progress.py

@@ -32,6 +32,11 @@ class Tqdm(tqdm):
     """
     maximum-compatibility tqdm-based progressbars
     """
+    BAR_FMT_DEFAULT = (
+        "{percentage:3.0f}%|{bar:10}|{desc} {bar:-10b}{n}/{total}"
+        " [{elapsed}<{remaining}, {rate_fmt:>11}{postfix}]"
+    )
+    BAR_FMT_NOTOTAL = "{desc} {bar:b}{n} [{elapsed}<??:??, {rate_fmt:>11}{postfix}]"
 
     def __init__(
         self,
@@ -40,10 +45,7 @@ def __init__(
         bytes=False,  # pylint: disable=W0622
         desc_truncate=None,
         leave=None,
-        bar_format=(
-            "{percentage:3.0f}%|{bar:10}|{desc} {bar:-10b}{n}/{total}"
-            " [{elapsed}<{remaining}, {rate_fmt:>11}{postfix}]"
-        ),
+        bar_format=None,
         **kwargs
     ):
         """
@@ -66,6 +68,11 @@ def __init__(
                 logging.getLogger(__name__).getEffectiveLevel()
                 >= logging.CRITICAL
             )
+        if bar_format is None:
+            if kwargs.get('total', getattr(iterable, '__len__', None)) is None:
+                bar_format = self.BAR_FMT_NOTOTAL
+            else:
+                bar_format = self.BAR_FMT_DEFAULT
         super(Tqdm, self).__init__(
             iterable=iterable,
             disable=disable,