configitems: change the `verify.skipflags` default value to avoid a py3 crash
The revlog and LFS modules use various `&` and `&=` operations with this value,
which no longer treats `None` as 0. Since nothing cares if it was actually set
in the config or not, just default to 0 for simplicity.
lib - sys sys
mercurial - sys sys
hgrc.d - sys sys
9diff.rc - sys sys
factotum.rc - sys sys
rc - sys sys
bin - sys sys
9diff - sys sys
hg - sys sys
sys - sys sys
lib - sys sys
python - sys sys
lib - sys sys
python2.5 - sys sys
site-packages - sys sys
hgext - sys sys
+ - sys sys
mercurial - sys sys
+ - sys sys
mercurial-VERSION-py2.5.egg-info - sys sys
src - sys sys
cmd - sys sys
hg - sys sys
+ - sys sys