[PATCH 2 of 5] unbundle: add a small comment to tag the bundle1 case as such

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at ens-lyon.org>
# Date 1486029338 -3600
#      Thu Feb 02 10:55:38 2017 +0100
# Node ID 904a482f2d70cd8859d09fe35af7d3e125ce632b
# Parent  9f7c2d6269c236f00bc7d8c896d6949d13cea637
# EXP-Topic pushcleanup
unbundle: add a small comment to tag the bundle1 case as such

This makes the code clearer to understand for someone new to it (or rusted)

diff -r 9f7c2d6269c2 -r 904a482f2d70 mercurial/exchange.py
--- a/mercurial/exchange.py	Thu Feb 02 10:51:04 2017 +0100
+++ b/mercurial/exchange.py	Thu Feb 02 10:55:38 2017 +0100
@@ -1763,6 +1763,7 @@
                         parts.append(part)
                 raise
         else:
+            # legacy case: bundle1 (changegroup 01)
             lockandtr[1] = repo.lock()
             r = cg.apply(repo, source, url)
     finally: