Update timeutils.py from oslo

This fix is related to oslo-incubator commits:
3bc6f79d794aee9d51abc0be10e846b971fae847
af76064855c5bb888e1a0d2800d1f49470e19091
df3f2bafbe76d78d017d40e7dc08909fee7dbe34

Change-Id: I1194df94d85d3dde29e81003c0c3db735c66b35f
Merge "Update timeutils.py from oslo"