RabbitVCS shows error emblem emblem-rabbitvcs-error.svg on all elements inside mercurial repository with Cyrillic name

Steps to reproduce:
1. Install Ubuntu 16.04 LTS
2. Install `rabbitvcs-nautilus` package and quit from Nautilus `nautilus -q`
3. Create repository directory with Cyrillic name as follows and open it with Nautilus:

```
mkdir ~/tmp/репозиторий_hg
hg init ~/tmp/репозиторий_hg
touch ~/tmp/репозиторий_hg/file
mkdir ~/tmp/репозиторий_hg/dir
cd ~/tmp/репозиторий_hg
hg config --edit # set username
hg addremove .
hg commit -m 'init'
nautilus ~/tmp/репозиторий_hg
```

Expected result:
all objects in the repository have green checkmark icon

Actual result:
all objects in the repository have bomb icon indicating error

Note: the log-file located in ~/.config/rabbitvcs/RabbitVCS.log contain many identical blocks -

```
2019-08-13 23:48:39,374 ERROR rabbitvcs.services.checkerservice org.freedesktop.DBus.Python.UnicodeEncodeError: Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/dbus/service.py", line 707, in _message_cb
    retval = candidate_method(self, *args, **keywords)
  File "/usr/lib/python2.7/dist-packages/rabbitvcs/services/checkerservice.py", line 175, in CheckStatus
    invalidate=invalidate)
  File "/usr/lib/python2.7/dist-packages/rabbitvcs/services/statuschecker.py", line 49, in check_status
    path_status = self.vcs_client.status(path, summary, invalidate)
  File "/usr/lib/python2.7/dist-packages/rabbitvcs/vcs/__init__.py", line 215, in status
    return client.status(path, summarize, invalidate)
  File "/usr/lib/python2.7/dist-packages/rabbitvcs/vcs/mercurial/__init__.py", line 209, in status
    all_statuses = self.statuses(path, invalidate=invalidate)
  File "/usr/lib/python2.7/dist-packages/rabbitvcs/vcs/mercurial/__init__.py", line 162, in statuses
    mercurial_statuses = self.repository.status(clean=True, unknown=True)
  File "/usr/lib/python2.7/dist-packages/mercurial/localrepo.py", line 1826, in status
    listsubrepos)
  File "/usr/lib/python2.7/dist-packages/mercurial/context.py", line 351, in status
    listunknown)
  File "/usr/lib/python2.7/dist-packages/mercurial/context.py", line 1620, in _buildstatus
    s = self._dirstatestatus(match, listignored, listclean, listunknown)
  File "/usr/lib/python2.7/dist-packages/mercurial/context.py", line 1589, in _dirstatestatus
    listclean, listunknown)
  File "/usr/lib/python2.7/dist-packages/mercurial/dirstate.py", line 1134, in status
    full=full).iteritems():
  File "/usr/lib/python2.7/dist-packages/mercurial/dirstate.py", line 1040, in walk
    traverse([d], alreadynormed)
  File "/usr/lib/python2.7/dist-packages/mercurial/dirstate.py", line 1000, in traverse
    entries = listdir(join(nd), stat=True, skip=skip)
UnicodeEncodeError: 'ascii' codec can't encode characters in position 42-52: ordinal not in range(128)
None
2019-08-13 23:48:39,448 ERROR rabbitvcs.services.checkerservice org.freedesktop.DBus.Python.UnicodeEncodeError: Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/dbus/service.py", line 707, in _message_cb
    retval = candidate_method(self, *args, **keywords)
...
```

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: mercurial-common 3.7.3-1ubuntu1.2
ProcVersionSignature: Ubuntu 4.4.0-157.185-generic 4.4.181
Uname: Linux 4.4.0-157-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.19
Architecture: amd64
CurrentDesktop: Unity
Date: Tue Aug 13 23:56:05 2019
PackageArchitecture: all
SourcePackage: mercurial
UpgradeStatus: No upgrade log present (probably fresh install)