subrepo: use code from 71ea5b2b9517 only if Python needs it (issue2795)
With Python >= 2.6 the original code already works correct, therefore the
fix for issue2556 on Python <= 2.5 broke relative subrepositories with
newer versions of Python.
#!/usr/bin/env python
# Filter output by the progress extension to make it readable in tests
import sys, re
for line in sys.stdin:
line = re.sub(r'\r+[^\n]', lambda m: '\n' + m.group()[-1:], line)
sys.stdout.write(line)
print