tests/test-execute-bit.t

hgweb: fallback to checking wsgireq.env for REPO_NAME for 3rd party hosting

Starting with d7fd203e36cc, SCM Manager began to 404 any repository access.
What's happening is that it is generating a python script that creates an hgweb
application (not hgwebdir), and launches hgweb via wsgicgi.  It must be setting
REPO_NAME in the process environment before launching this script, which gets
picked up and put into wsgireq.env when wsgicgi launches the hgweb application.
>From there, other variables (notably 'apppath' and 'dispatchpath') are
constructed differently.

  d7fd203e36cc^ (working):

    apppath: /hg/eng/devsetup
    dispatchpath:
    pathinfo: /eng/devsetup
    reponame: eng/devsetup

  d7fd203e36cc:

    apppath: /hg
    dispatchpath: eng/devsetup
    pathinfo: /eng/devsetup
    reponame: None
    REPO_NAME: eng/devsetup

Rather than having an existing installation break when Mercurial is upgraded,
just resume checking the environment.  I have no idea how many other hosting
solutions would break without restoring this.

#require execbit

  $ hg init
  $ echo a > a
  $ hg ci -Am'not executable'
  adding a

  $ chmod +x a
  $ hg ci -m'executable'
  $ hg id
  79abf14474dc tip

Make sure we notice the change of mode if the cached size == -1:

  $ hg rm a
  $ hg revert -r 0 a
  $ hg debugstate
  n   0         -1 unset               a
  $ hg status
  M a

  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id
  d69afc33ff8a
  $ test -x a && echo executable -- bad || echo not executable -- good
  not executable -- good