[PATCH STABLE] tests: run "cwd was removed" test only if cwd can actually be removed

[Danek Duvall]

Yuya Nishihara wrote:

> # HG changeset patch
> # User Yuya Nishihara <yuya at tcha.org>
> # Date 1477489806 -32400
> #      Wed Oct 26 22:50:06 2016 +0900
> # Branch stable
> # Node ID d389b88b942adb330819437ef46d1b9acb4392d7
> # Parent  b9f7b0c10027764cee77f9c6d61877fcffea837f
> tests: run "cwd was removed" test only if cwd can actually be removed
> 
> On some platforms, cwd can't be removed. In which case, util.unlinkpath()
> continues with no error since the failure isn't critical.

The problem here is a bit more specific: while Linux (for example) prevents
you from removing cwd when referring to it as ".", Solaris prevents you
from removing it under all names.  So because that failure isn't critical,
the cwd ends up remaining behind on Solaris because it's done via the full
path.  It might make sense to be more specific in the name, too, though I'm
not sure what to suggest.

There's also a second test that has some related output:

    --- a/tests/test-rebase-scenario-global.t
    +++ b/tests/test-rebase-scenario-global.t
    @@ -758,8 +758,6 @@ Test that rebase is not confused by $CWD
       $ hg commit -m 'second source with subdir'
       $ hg rebase -b . -d 1 --traceback
       rebasing 2:779a07b1b7a0 "first source commit"
    -  current directory was removed
    -  (consider changing to repo root: $TESTTMP/cwd-vanish)
       rebasing 3:a7d6f3a00bf3 "second source with subdir" (tip)
       saved backup bundle to $TESTTMP/cwd-vanish/.hg/strip-backup/779a07b1b7a0-853e0073-backup.hg (glob)

is what I had to remove temporarily.

Thanks,
Danek