Move kazoo to testenv requirements

Kazoo is an optional dependency of taskflow: it is required when
zookeeper persistence layer or if kazoo_utils are used. So we should
move it to where these type of optional requirements are currently
placed.

Change-Id: I9d1605af266f4a79fd6ebfee2d68a4f4f7413022

test-requirements.txt

@@ -5,6 +5,4 @@ mock>=1.0
 python-subunit>=0.0.18
 testrepository>=0.0.17
 testtools>=0.9.34
-# ZooKeeper
-kazoo>=1.3.1
 zake>=0.0.13

tox-tmpl.ini

@@ -17,6 +17,7 @@ deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
        alembic>=0.4.1
        psycopg2
+       kazoo>=1.3.1
 commands = python setup.py testr --slowest --testr-args='{posargs}'
 
 [tox:jenkins]

tox.ini

@@ -48,6 +48,7 @@ deps = -r{toxinidir}/requirements.txt
     -r{toxinidir}/test-requirements.txt
     alembic>=0.4.1
     psycopg2
+    kazoo>=1.3.1
 commands = python setup.py testr --slowest --testr-args='{posargs}'
 
 [tox:jenkins]