Rename requires files to standard names.

Rename tools/pip-requires to requirements.txt and tools/test-requires
to test-requirements.txt. These are standard files, and tools in the
general world are growing intelligence about them.

Fixes: bug #1179008
Change-Id: I033876ec304fea97c66365c16bcf0cccaa1d810e

README.rst

@@ -27,5 +27,5 @@ To run tests in virtualenvs (preferred):
 
 To run tests in the current environment:
 
-  sudo pip install -r tools/pip-requires
+  sudo pip install -r requirements.txt
   nosetests

tox.ini

@@ -9,8 +9,8 @@ setenv = VIRTUAL_ENV={envdir}
          NOSE_OPENSTACK_YELLOW=0.025
          NOSE_OPENSTACK_SHOW_ELAPSED=1
          NOSE_OPENSTACK_STDOUT=1
-deps = -r{toxinidir}/tools/pip-requires
-       -r{toxinidir}/tools/test-requires
+deps = -r{toxinidir}/requirements.txt
+       -r{toxinidir}/test-requirements.txt
 commands =
   python tools/patch_tox_venv.py
   nosetests --with-doctest --exclude-dir=tests/testmods {posargs}