hghave: add "py3k" feature to check whether test runs with Python 3.x
This patch adds "py3k" feature to check whether test runs with Python
3.x.
This check is needed for portability of test code: for example, in the
default, modules are imported relatively first with python 2.x, but
imported absolutely with Python 3.x.
fixbundle() {
grep -v 'saving bundle' | grep -v 'saved backup' | \
grep -v added | grep -v adding | \
grep -v "unable to find 'e' for patching" | \
grep -v "e: No such file or directory"
}