Just unify having a single requirements.txt file

The difference between the py2 and py3 requirements file
is marginal and it does not harm py3 from having additional
dependencies that aren't used anyway so just have a single
requirements file.

Change-Id: I969ea61f68a2c7c2d7fb4d38e6e1d3daa59b0d40

requirements-py3.txt

@@ -1,30 +0,0 @@
-# The order of packages is significant, because pip processes them in the order
-# of appearance. Changing the order has an impact on the overall integration
-# process, which may cause wedges in the gate later.
-
-# See: https://bugs.launchpad.net/pbr/+bug/1384919 for why this is here...
-pbr>=0.6,!=0.7,<1.0
-
-# Packages needed for using this library.
-
-# Python 2->3 compatibility library.
-six>=1.9.0
-
-# Enum library made for <= python 3.3
-enum34
-
-# Very nice graph library
-networkx>=1.8
-
-# Used for backend storage engine loading.
-stevedore>=1.3.0,<1.4.0  # Apache-2.0
-
-# Used for structured input validation
-jsonschema>=2.0.0,<3.0.0
-
-# For common utilities
-oslo.utils>=1.4.0,<1.5.0                       # Apache-2.0
-oslo.serialization>=1.4.0,<1.5.0               # Apache-2.0
-
-# For deprecation of things
-debtcollector>=0.3.0,<0.4.0  # Apache-2.0

tox.ini

@@ -16,7 +16,8 @@ envlist = cover,
 usedevelop = True
 install_command = pip install {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
-deps = -r{toxinidir}/test-requirements.txt
+deps = -r{toxinidir}/requirements.txt
+    -r{toxinidir}/test-requirements.txt
 commands = python setup.py testr --slowest --testr-args='{posargs}'
 
 [testenv:docs]
@@ -33,7 +34,7 @@ commands = flake8 {posargs}
 
 [testenv:pylint]
 setenv = VIRTUAL_ENV={envdir}
-deps = -r{toxinidir}/requirements-py2.txt
+deps = {[testenv]deps}
     pylint==0.26.0
 commands = pylint --rcfile=pylintrc taskflow
 
@@ -62,14 +63,12 @@ import_exceptions = six.moves
 [testenv:py26]
 basepython = python2.6
 deps = {[testenv]deps}
-    -r{toxinidir}/requirements-py2.txt
     MySQL-python
     eventlet>=0.15.1
     SQLAlchemy>=0.7.8,<=0.8.99
 
 [testenv:py27]
 deps = {[testenv]deps}
-    -r{toxinidir}/requirements-py2.txt
     MySQL-python
     eventlet>=0.15.1
     SQLAlchemy>=0.7.8,<=0.9.99
@@ -81,26 +80,22 @@ commands =
 
 [testenv:py33]
 deps = {[testenv]deps}
-    -r{toxinidir}/requirements-py3.txt
     SQLAlchemy>=0.7.8,<=0.9.99
     PyMySQL>=0.6.2
 
 [testenv:py34]
 deps = {[testenv]deps}
-    -r{toxinidir}/requirements-py3.txt
     SQLAlchemy>=0.7.8,<=0.9.99
     PyMySQL>=0.6.2
 
 [testenv:py26-sa7-mysql]
 basepython = python2.6
 deps = {[testenv]deps}
-    -r{toxinidir}/requirements-py2.txt
     SQLAlchemy>=0.7.8,<=0.7.99
     MySQL-python
 
 [testenv:py27-sa8-mysql]
 basepython = python2.7
 deps = {[testenv]deps}
-    -r{toxinidir}/requirements-py2.txt
     SQLAlchemy>=0.8,<=0.8.99
     MySQL-python