Reverted the file permission

Reverted the file permission

There are some files whose permissions are changed unintendedly.
Revert all of them.

mode change 100644 <= 100755 functest/core/pytest_suite_runner.py
mode change 100644 <= 100755 functest/opnfv_tests/openstack/vping/vping_base.py
mode change 100644 <= 100755 functest/utils/openstack_tacker.py
mode change 100644 <= 100755 functest/tests/unit/odl/test_odl.py
mode change 100644 <= 100755 requirements.txt
mode change 100644 <= 100755 test-requirements.txt

Historical comments that changed the permission for reference
changeID: Ia02760fd98aaab59a6cf0a90a2020b76e0c92df6
changeID: Id6815f96a11f2918bc2c7bc1c33f38c3f5754e11
changeID: Ic8c01b9b7ed86d3bdd9f5125504bc47f46a37700
changeID: I9f1a408f0e43bff4499575fa57cabd1a83d99b3a

Change-Id: I1deadd77cc78f2186f82de79233aabe97ac21b26
Signed-off-by: helenyao <yaohelan@huawei.com>