Temporarily pin ws4py sub-dependency to v0.3.4 (#51)

As we can see in #49 and #50, our integration tests broke due to a
recent ws4py release. Until we figure out how to fix the problem
upstream, we pin this dependency to make our tests run again.

setup.py

@@ -34,6 +34,9 @@ def read_relative_file(filename):
     keywords='lxd lxc containers environments orchestration devops',
     zip_safe=False,
     install_requires=[
+        # This requirement below is actually a pylxd dependency, but a recent ws4py release broke
+        # lxdock. Until we figure out how to fix the problem upstream, we pin ws4py to v0.3.4 here.
+        'ws4py==0.3.4',
         'colorlog>=2.0,<3.0',
         'pylxd>=2.2,<3.0',
         'PyYAML>=3.0,<4.0',