Fix run_tests.sh

With merge of commit:
https://github.com/stackforge/python-manilaclient/commit/ce35f9b847ab21df6f8e8aa6791b3c628cd68a1b

File run_tests.sh became broken, it tries to use old names of renamed files with dependencies:
tools/pip-requires → requirements.txt
tools/test-requires → test-requirements.txt

Change-Id: Id83f55201ef01a9c3f7ee37406ac6070c4b14c5e
Closes-Bug: #1342538