[PATCH 1 of 5 postargs] httppeer: do less splitting on httpheader value

[Augie Fackler]

# HG changeset patch
# User Augie Fackler <augie at google.com>
# Date 1457713490 18000
#      Fri Mar 11 11:24:50 2016 -0500
# Node ID 4c628e9d4647100d2beed4aeb53dd01e50bf4770
# Parent  8199ae50cd4b8bd89bf3d9b836ee10b9e49ba759
# EXP-Topic batch
httppeer: do less splitting on httpheader value

We only care about the first value split off, so only split off the first
value.

diff --git a/mercurial/httppeer.py b/mercurial/httppeer.py
--- a/mercurial/httppeer.py
+++ b/mercurial/httppeer.py
@@ -112,7 +112,7 @@ class httppeer(wireproto.wirepeer):
         if len(args) > 0:
             httpheader = self.capable('httpheader')
             if httpheader:
-                headersize = int(httpheader.split(',')[0])
+                headersize = int(httpheader.split(',', 1)[0])
         if headersize > 0:
             # The headers can typically carry more data than the URL.
             encargs = urllib.urlencode(sorted(args.items()))