bundle: do no check the changegroup version if no changegroup is included
We don't need to check the compatibility of something we will not use.
In practice this was getting in the was of `streamv2` bundles on a narrow
repository as the 'cg.version=02' value was rejected by this checks.
$ cat <<EOF >> $HGRCPATH
> [extensions]
> purge =
> EOF
$ hg init test
$ cd test
$ echo a > changed
$ echo a > removed
$ echo a > source
$ hg ci -Am addfiles
adding changed
adding removed
adding source
$ echo a >> changed
$ echo a > added
$ hg add added
$ hg rm removed
$ hg cp source copied
$ hg diff --git > ../unknown.diff
Test adding on top of an unknown file
$ hg up -qC 0
$ hg purge
$ echo a > added
$ hg import --no-commit ../unknown.diff
applying ../unknown.diff
file added already exists
1 out of 1 hunks FAILED -- saving rejects to file added.rej
abort: patch failed to apply
[20]
Test modifying an unknown file
$ hg revert -aq
$ hg purge
$ hg rm changed
$ hg ci -m removechanged
$ echo a > changed
$ hg import --no-commit ../unknown.diff
applying ../unknown.diff
abort: cannot patch changed: file is not tracked
[20]
Test removing an unknown file
$ hg up -qC 0
$ hg purge
$ hg rm removed
$ hg ci -m removeremoved
created new head
$ echo a > removed
$ hg import --no-commit ../unknown.diff
applying ../unknown.diff
abort: cannot patch removed: file is not tracked
[20]
Test copying onto an unknown file
$ hg up -qC 0
$ hg purge
$ echo a > copied
$ hg import --no-commit ../unknown.diff
applying ../unknown.diff
abort: cannot create copied: destination already exists
[20]
$ cd ..