Rename requirements files to standard names.

Change-Id: I0385ac9f8336a8c2e45b0fa6ed062b6b23a182aa
Reviewed-on: https://review.openstack.org/33351
Reviewed-by: James E. Blair <corvus@inaugust.com>
Approved: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Tested-by: Jenkins

tox.ini

@@ -5,8 +5,8 @@ envlist = pep8, pyflakes, py27
 # Set STATSD env variables so that statsd code paths are tested.
 setenv = STATSD_HOST=localhost
          STATSD_PORT=8125
-deps = -r{toxinidir}/tools/pip-requires
-       -r{toxinidir}/tools/test-requires
+deps = -r{toxinidir}/requirements.txt
+       -r{toxinidir}/test-requirements.txt
 commands = nosetests --logging-format="%(asctime)s %(name)-32s %(levelname)-8s %(message)s" {posargs}
 
 [tox:jenkins]
@@ -20,7 +20,7 @@ setenv = NOSE_WITH_COVERAGE=1
 
 [testenv:pyflakes]
 deps = pyflakes
-       -r{toxinidir}/tools/pip-requires
+       -r{toxinidir}/requirements.txt
 commands = pyflakes zuul setup.py
 
 [testenv:venv]