Disable the progress meter when trace is enabled

The trace output often interfers with the progress meter, so its
easier to just disable the progress meter if trace is active.
Its already verbose enough to let the user know we are working,
which is all the progress meter is there for anyway.

Signed-off-by: Shawn O. Pearce <sop@google.com>

progress.py

@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import sys
+from trace import IsTrace
 
 class Progress(object):
   def __init__(self, title, total=0):
@@ -25,6 +26,9 @@ class Progress(object):
   def update(self, inc=1):
     self._done += inc
 
+    if IsTrace():
+      return
+
     if self._total <= 0:
       sys.stderr.write('\r%s: %d, ' % (
         self._title,
@@ -43,6 +47,9 @@ class Progress(object):
         sys.stderr.flush()
 
   def end(self):
+    if IsTrace():
+      return
+
     if self._total <= 0:
       sys.stderr.write('\r%s: %d, done.  \n' % (
         self._title,