tests/test-revert-unknown.t

osx: override default exclude filter for pkgbuild

To quote `man 1 pkgbuild`:

     --filter filter-expression
                 By default, --root will include the entire contents of the
                 given root-path in the package payload, except for any .svn
                 or CVS directories, and any .DS_Store files. You can override
                 these default filters by specifying one or more --filter
                 options. Each filter-expression is an re_format(7)
                 ``extended'' expression: any path in the root which matches
                 any of the given expressions will be excluded from the pack-
                 age payload. (Note that specifying even one --filter inhibits
                 the default filters, so you must respecify the default fil-
                 ters if you still want them to be used.)

It turns out the default filter these days *also* includes .git and
.hg. Notice how that filter expression is a regular expression?  That
(presumably unintentionally) prevents a file named "chg" or "_hg" from
getting included in the distribution. Many many thanks to spectral@
for trying to include a _hg file which led us to figure this bug out.

Bug filed with Apple for this as rdar://problem/32437369, mentioning
both the gap in documentation and the wrong defaults.

  $ hg init
  $ touch unknown

  $ touch a
  $ hg add a
  $ hg ci -m "1"

  $ touch b
  $ hg add b
  $ hg ci -m "2"

Should show unknown

  $ hg status
  ? unknown
  $ hg revert -r 0 --all
  removing b

Should show unknown and b removed

  $ hg status
  R b
  ? unknown

Should show a and unknown

  $ ls
  a
  unknown