debugignore: catch the case when ignore.includepat doesn't exist
In testing of my recent addition of a debugignore command, some of my MacHg
users uncovered the exceptional case that if there is no ignore patterns of any
kind then a traceback occurred. Catch and fix this case.
syntax: glob
*.elc
*.orig
*.rej
*~
*.mergebackup
*.o
*.so
*.pyd
*.pyc
*.pyo
*$py.class
*.swp
*.prof
\#*\#
.\#*
tests/.coverage*
tests/annotated
tests/*.err
build
contrib/hgsh/hgsh
dist
doc/*.[0-9]
doc/*.[0-9].gendoc.txt
doc/*.[0-9].{x,ht}ml
MANIFEST
patches
mercurial/__version__.py
mercurial.egg-info
Output/Mercurial-*.exe
.DS_Store
tags
cscope.*
i18n/hg.pot
locale/*/LC_MESSAGES/hg.mo
# files installed with a local --pure build
mercurial/base85.py
mercurial/bdiff.py
mercurial/diffhelpers.py
mercurial/mpatch.py
mercurial/osutil.py
mercurial/parsers.py
syntax: regexp
^\.pc/
^\.(pydev)?project