bundle: use bundle2 if repository uses general delta

As bundle1 does not support generaldelta, this would mean recomputing delta at
bundle time. This is similar to what we do for strip and shelve and was tracked
as issue4865.

mercurial/cmdutil.py

@@ -3374,6 +3374,8 b' def parsebundletype(repo, spec):'
 
     if version is None:
         version = '01'
+        if 'generaldelta' in repo.requirements:
+            version = '02'
     else:
         try:
             version = _bundleversionspecs[version]

mercurial/commands.py

@@ -1223,7 +1223,7 b' def bundle(ui, repo, fname, dest=None, *'
     specify a compression, a bundle version or both using a dash
     (comp-version). The available compression methods are: none, bzip2,
     and gzip (by default, bundles are compressed using bzip2). The
-    available format are: v1, v2 (default to v1).
+    available format are: v1, v2 (default to most suitable).
 
     The bundle file can then be transferred using conventional means
     and applied to another repository with the unbundle or pull