removed horizon from test_requestent.txt

Horizon in the test_requestent.text causes failure
when installing devstack.
For the problem of depending on horizon,
we can move horizon.tar.gz to tox.ini
Change-Id: Ifcc109d1a8cc6df9baced39b76159e04505db3b1

test-requirements.txt

@@ -3,9 +3,6 @@
 # process, which may cause wedges in the gate later.
 # Hacking already pins down pep8, pyflakes and flake8
 
-# Testing Requirements
-http://tarballs.openstack.org/horizon/horizon-master.tar.gz#egg=horizon
-
 hacking!=0.13.0,<0.14,>=0.12.0 # Apache-2.0
 coverage!=4.4,>=4.0 # Apache-2.0
 django-nose>=1.4.4 # BSD

tox.ini

@@ -21,6 +21,7 @@ whitelist_externals = /bin/bash
                       find
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
+       http://tarballs.openstack.org/horizon/horizon-master.tar.gz
 commands =
     rm -f .testrepository/times.dbm
     find . -type f -name "*.pyc" -delete