Force pylxd to a private fork of mine

lxdock is currently broken with LXD 2.14+ and pylxd hasn't released a
fix yet. Our only solution for now is to point to a private branch of
mine including fixes proposed at canonical/pylxd#234.

setup.py

@@ -35,13 +35,17 @@ def read_relative_file(filename):
     zip_safe=False,
     install_requires=[
         'colorlog>=2.0,<3.0',
-        'pylxd>=2.2,<3.0',
+        'pylxd==2.2.4',
         'python-dotenv>=0.6',
         'PyYAML>=3.0,<4.0',
         'voluptuous>=0.9,<1.0',
         # TODO: find why requests >= 2.16 breaks our stuff. See #81
         'requests>=2.5.1,<2.16',
     ],
+    dependency_links=[
+        # Temporary, until https://github.com/lxc/pylxd/pull/234 is merged and released
+        'git+https://github.com/hsoft/pylxd.git@fix-for-lxdock#egg=pylxd-2.2.4',
+    ],
     tests_require=[
         'pytest',
     ],

tox.ini

@@ -10,6 +10,9 @@ setenv =
 commands =
     py.test
 
+# Temporary while we need a dev version of pylxd
+install_command = pip install --process-dependency-links {opts} {packages}
+
 [testenv:lint]
 deps =
     flake8