tests/failfilemerge.py

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

# extension to emulate interrupting filemerge._filemerge

from __future__ import absolute_import

from mercurial import (
    error,
    extensions,
    filemerge,
)

def failfilemerge(filemergefn,
                  premerge, repo, wctx, mynode, orig, fcd, fco, fca,
                  labels=None):
    raise error.Abort("^C")
    return filemergefn(premerge, repo, mynode, orig, fcd, fco, fca, labels)

def extsetup(ui):
    extensions.wrapfunction(filemerge, '_filemerge',
                            failfilemerge)