tests/test-nested-repo.t

remotenames: rename related file and storage dir to logexchange

This patch renames remotenames.py to logexchange.py, test-remotenames.t to
test-logexchange.t. Also this patch renames the directory in which the data is
stored from remotenames to logexchange. After this patch, data about bookmarks
and branches from a server we pull is stored in
`.hg/logexchange/(bookmarks|branches)` files.

Thanks to smf for the suggestion.

Differential Revision: https://phab.mercurial-scm.org/D1607

  $ hg init a
  $ cd a
  $ hg init b
  $ echo x > b/x

Should print nothing:

  $ hg add b
  $ hg st

  $ echo y > b/y
  $ hg st

Should fail:

  $ hg st b/x
  abort: path 'b/x' is inside nested repo 'b' (glob)
  [255]
  $ hg add b/x
  abort: path 'b/x' is inside nested repo 'b' (glob)
  [255]

Should fail:

  $ hg add b b/x
  abort: path 'b/x' is inside nested repo 'b' (glob)
  [255]
  $ hg st

Should arguably print nothing:

  $ hg st b

  $ echo a > a
  $ hg ci -Ama a

Should fail:

  $ hg mv a b
  abort: path 'b/a' is inside nested repo 'b' (glob)
  [255]
  $ hg st

  $ cd ..