changegroup: add version argument to getchangegroup

For some obscure reasons (probably upsetting a Greek goddess),
getchangegroup did not had a 'version' argument to control the changegroup
version. We fixes this to allow cg02 to be used with 'hg bundle' in the future.

mercurial/changegroup.py

@@ -645,7 +645,8 b' def computeoutgoing(repo, heads, common)'
         heads = cl.heads()
     return discovery.outgoing(cl, common, heads)
 
-def getchangegroup(repo, source, heads=None, common=None, bundlecaps=None):
+def getchangegroup(repo, source, heads=None, common=None, bundlecaps=None,
+                   version='01'):
     """Like changegroupsubset, but returns the set difference between the
     ancestors of heads and the ancestors common.
 
@@ -655,7 +656,8 b' def getchangegroup(repo, source, heads=N'
     current discovery protocol works.
     """
     outgoing = computeoutgoing(repo, heads, common)
-    return getlocalchangegroup(repo, source, outgoing, bundlecaps=bundlecaps)
+    return getlocalchangegroup(repo, source, outgoing, bundlecaps=bundlecaps,
+                               version=version)
 
 def changegroup(repo, basenodes, source):
     # to avoid a race we use changegroupsubset() (issue1320)