nrpe check_swift_storage.py fails when replication_last is null (float expected)

[Alvaro Uria]

When there is a permissions issue ie. on /var/cache/swift/object.recon (uid/gid=0 instead of swift user), the following command (curl localhost:6000/recon/replication/object) would return:
"""
{"replication_last": null, "replication_stats": null, "object_replication_last": null, "replication_time": null, "object_replication_time": null}
"""

That makes check_swift_storage.py fail:
"""
Traceback (most recent call last):
  File "/usr/local/lib/nagios/plugins/check_swift_storage.py", line 118, in <module>
    results.extend(check_replication(base_url, args.check_replication))
  File "/usr/local/lib/nagios/plugins/check_swift_storage.py", line 74, in check_replication
    repl_last = datetime.datetime.fromtimestamp(j["object_replication_last"])
TypeError: a float is required
"""

nrpe check should catch null values and trigger a critical error.

[Alvaro Uria (aluria)]

Proposed change:
https://review.openstack.org/#/c/446490/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/460641

[OpenStack Infra (hudson-openstack)]

Change abandoned by Alvaro Uría (<email address hidden>) on branch: master
Review: https://review.openstack.org/460641
Reason: wrong change-id. Set abandoned in favor of 446490.

[Alvaro Uria (aluria)]

Change reviewed and pending to be merged:
https://review.openstack.org/#/c/446490/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/446490
Committed: https://git.openstack.org/cgit/openstack/charm-swift-storage/commit/?id=d59759259e8537af596976f7f8d8adc02f9e75be
Submitter: Jenkins
Branch: master

commit d59759259e8537af596976f7f8d8adc02f9e75be
Author: Alvaro Uria <email address hidden>
Date: Thu Apr 27 18:50:14 2017 +0200

    Support null values on recon/replication module

    Update on nrpe check check_swift_storage:
     * Refactor check_replication function
     * Raise STATUS_CRIT on null values
     * Clean code per flake8 and previous review
     * Add unit_test for nrpe check check_swift_storage.py

    Change-Id: Ie076b8ea56f66c1e15a9bfe2e400b49f968fa4ed
    Closes-Bug: #1673441
    Signed-off-by: Alvaro Uria <email address hidden>