progress: hide progress bar when --quiet

We want progress bars in the default output mode, but not when the
user specifies --quiet.  Add a setting to the Progress bar class so
it takes care of not displaying anything itself rather than having
to update every subcommand to conditionally setup & call the object.

Change-Id: I1134993bffc5437bc22e26be11a512125f10597f
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/303225
Reviewed-by: Raman Tenneti <rtenneti@google.com>
Tested-by: Mike Frysinger <vapier@google.com>

progress.py

@@ -42,7 +42,8 @@ def duration_str(total):
 
 
 class Progress(object):
-  def __init__(self, title, total=0, units='', print_newline=False, delay=True):
+  def __init__(self, title, total=0, units='', print_newline=False, delay=True,
+               quiet=False):
     self._title = title
     self._total = total
     self._done = 0
@@ -54,6 +55,13 @@ class Progress(object):
     self._show_jobs = False
     self._active = 0
 
+    # When quiet, never show any output.  It's a bit hacky, but reusing the
+    # existing logic that delays initial output keeps the rest of the class
+    # clean.  Basically we set the start time to years in the future.
+    if quiet:
+      self._show = False
+      self._start += 2**32
+
   def start(self, name):
     self._active += 1
     if not self._show_jobs: