Fixes glance aspect of lp 837464
Prevously only Zulu time was supported in the changes-since filter,
i.e. timestamps formatted as %Y-%m-%dT%H:%M:%SZ
We now support arbitrary timezones, with the offset from UTC expressed
via the ISO 8601 ±hh:mm notation.
Microsecond accurracy is also optionally supported in timestamps.
Notes:
- glance.common.utils.parse_isotime(), isotime(), & normalize_time()
are prime candidates for promotion to openstack-common, as these
methods will be useful in nova also
- this patch introduces a new dependency on python-iso8601, which
has already been packaged for Fedora, EPEL and Ubuntu/Debian.
Change-Id: I4c80522bcaa14feef93f5f9fbcaaca6a74b6a5f4
f8f9f17112