Move sphinxcontrib-httpdomain to test-requirements

The sphinxcontrib-httpdomain is now in the global-requirements list, so,
it'll be better to track *all* requirements in the corresponding files.

Change-Id: I6cd9eb8982cd49be1c59680a16d66acd30b9a29f

test-requirements.txt

@@ -16,6 +16,7 @@ docutils==0.9.1
 oslo.sphinx
 python-subunit
 sphinx>=1.1.2,<1.2
+sphinxcontrib-httpdomain
 sphinxcontrib-pecanwsme>=0.5
 testrepository>=0.0.17
 testscenarios>=0.4

tox.ini

@@ -35,13 +35,11 @@ commands =
 [testenv:docs]
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-       sphinxcontrib-httpdomain
 commands = python setup.py build_sphinx
 
 [testenv:venv]
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-       sphinxcontrib-httpdomain
 commands = {posargs}
 
 [flake8]