tests/sitecustomize.py

subrepo: make "_sanitize()" work

"_sanitize()" was introduced by 224e96078708 on "stable" branch, but
it has done nothing for sanitizing since 224e96078708.

"_sanitize()" assumes "Visitor" design pattern:

    "os.walk()" should invoke specified function ("v" in this case)
    for each directory elements under specified path

but "os.walk()" assumes "Iterator" design pattern:

    callers of it should drive loop to scan each directory elements
    under specified path by themselves with the returned generator
    object

Because of this mismatching, "_sanitize()" just discards the generator
object returned by "os.walk()" and does nothing for sanitizing.

This patch makes "_sanitize()" work.

This patch also changes the format of warning message to show each
unlinked files, for multiple appearances of "potentially hostile
.hg/hgrc".

try:
    import coverage
    getattr(coverage, 'process_startup', lambda: None)()
except ImportError:
    pass