Make gclient_utils work with Python 3

It seems like line is always a string, not bytes; this change
seems to make it work with both Python 2 and 3 (at least,
"gclient sync" looks correct and doesn't throw exceptions)

Bug: 984182
Change-Id: Iaa09e08d4eda0ccb54afa5598bac6231319d6c3d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1744766
Auto-Submit: Christian Biesinger <cbiesinger@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>

gclient_utils.py

@@ -643,13 +643,13 @@ class GitFilter(object):
 
   def __call__(self, line):
     # git uses an escape sequence to clear the line; elide it.
-    esc = line.find(chr(0o33).encode())
+    esc = line.find(chr(0o33))
     if esc > -1:
       line = line[:esc]
     if self.predicate and not self.predicate(line):
       return
     now = time.time()
-    match = self.PERCENT_RE.match(line.decode())
+    match = self.PERCENT_RE.match(line)
     if match:
       if match.group(1) != self.progress_prefix:
         self.progress_prefix = match.group(1)