[PATCH] pyflakes: use pycompat.pickles to prevent error

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at ens-lyon.org>
# Date 1466726683 -7200
#      Fri Jun 24 02:04:43 2016 +0200
# Node ID a40bead90ee0999be32fe0b2fdc5d39985c7a57b
# Parent  6d96658a22b0fc1eb210c99c5629dd69fedf3006
pyflakes: use pycompat.pickles to prevent error

The pyflakes in my test box complain about pickle in pycompat.

  mercurial/pycompat.py:17: 'pickle' imported but unused

diff -r 6d96658a22b0 -r a40bead90ee0 mercurial/pycompat.py
--- a/mercurial/pycompat.py	Thu Jun 23 18:21:25 2016 +0100
+++ b/mercurial/pycompat.py	Fri Jun 24 02:04:43 2016 +0200
@@ -15,6 +15,7 @@ try:
     pickle.dumps
 except ImportError:
     import pickle
+    pickle.dumps # silence pyflakes
 
 try:
     import cStringIO as io