tests/test-merge8.t

resourceutil: account for the non-resource-like file hierarchy under py2exe

After 9e367157a990, config files for py2exe were expected to be in
C:\Program Files\Mercurial\mercurial\defaultrc because of the implied resource
structure of 'mercurial.defaultrc.*.rc', relative to the executable.
Accomodating this would require changes to the WIX and Inno scripts (and perhaps
the script that generates the WIX script), as well as 3rd party bundlers like
TortoiseHg.  But these files aren't read as resources anyway- they fall back to
the filesystem APIs.  (If we really wanted to carry on the charade, the
installer would have to also sprinkle various empty __init__.py files around.)

Instead, this simply prunes the 'mercurial.' portion of the resource name when
run with py2exe.  (PyOxidizer uses the resources API, not the filesystem
fallback, so it is unaffected.)  Since this hack only affects the py2 Windows
installers and is less risky, I think it's reasonable.  We haven't needed to
load any 3rd party resource up to this point, and would have to make packaging
changes anyway to handle that.

Differential Revision: https://phab.mercurial-scm.org/D8058

Test for changeset ba7c74081861
(update dirstate correctly for non-branchmerge updates)
  $ hg init a
  $ cd a
  $ echo a > a
  $ hg add a
  $ hg commit -m a
  $ cd ..
  $ hg clone a b
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd a
  $ hg mv a b
  $ hg commit -m move
  $ echo b >> b
  $ hg commit -m b
  $ cd ../b
  $ hg pull ../a
  pulling from ../a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets e3c9b40284e1:772b37f1ca37
  (run 'hg update' to get a working copy)
  $ hg update
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ cd ..