scripts/maintenance: Fix dates (tomorrow vs. today, etc.)

[wking]

Builds on #76; review that first.

tag-aws.sh is using grafiti, whose tagPatterns takes jq expressions. We've been using strftime since the script landed in 82bdd9f (coreos/tectonic-installer#1239). jq's strftime doesn't respect your configured $TZ, but the coming jq 1.6 will add strflocaltime which does. jq uses seconds since the epoch for date-time values. You can test the new construct with:

$ jq --null-input --raw-output 'now + 24*60*60 | strftime("%Y-%m-%d")'
2018-07-27

-d is not part of the POSIX date specification, but it (and the tomorrow value) are supported by GNU Coreutils [6,7]. But we've been using -d in clean-aws.sh for a while now, so this is now a new dependency.

I've also dropped date_override, since we can just set date_string directly. And I've shuffled around some of the conditionals to avoid calling the date (or jq) command needlessly when --date-override is set.

I've also replaced the multiple date calls in clean-aws.sh with a single call to jq. jq was already a required dependency for this script, and only needing a single child process is much faster:

$ time for i in $(seq 100); do A="$(jq --null-input '[["%Y-%m-%d", "%Y-%-m-%-d", "%m-%d-%Y", "%m-%-d-%-Y", "%-m-%-d-%-Y", "%d-%m-%Y", "%d-%-m-%-Y"][] | . as $format | [now, now - 24*60*60][] | strftime($format)]')"; done

real   0m0.256s
user   0m0.186s
sys    0m0.077s
$ time for i in $(seq 100); do A="$(date "+%Y-%m-%d" -d "-1 day")\",\"$(date "+%Y-%-m-%-d" -d "-1 day")\",\"$(date "+%m-%-d-%-Y" -d "-1 day")\",\"$(date "+%-m-%-d-%-Y" -d "-1 day")\",\"$(date "+%d-%m-%-Y" -d "-1 day")\",\"$(date "+%d-%-m-%-Y" -d "-1 day")\",\"$(date +%m-%d-%Y)\",\"$(date +%d-%m-%Y)\",\"$(date +%d-%-m-%Y)\",\"$(date +%Y-%m-%d)\",\"$(date +%Y-%-m-%-d)"; done

real   0m1.358s
user   0m0.604s
sys    0m0.832s

and that's despite the fact that the old approach skipped some formats for today (e.g. %m-%-d-%-Y had been only used to format yesterday).

[wking]

The e2e-aws errors were more EIP exhaustion:

2 error(s) occurred:

* module.vpc.aws_eip.nat_eip[0]: 1 error(s) occurred:

* aws_eip.nat_eip.0: Error creating EIP: AddressLimitExceeded: The maximum number of addresses has been reached.
	status code: 400, request id: 6243c771-d3fe-42c7-8607-a578bdfff21e
* module.vpc.aws_eip.nat_eip[2]: 1 error(s) occurred:

* aws_eip.nat_eip.2: Error creating EIP: AddressLimitExceeded: The maximum number of addresses has been reached.
	status code: 400, request id: d90dddb6-66cd-4966-baf2-8d0af2fc946f

I've got a script cleaning out leaked EIPs now, so we should be clear on that front.

/retest

[yifan-gu]

/lgtm

Good found!

[wking]

PR needs rebase.

Rebased with c1d19a7 -> 184a0bf. I think this was just the context change due to #75, but @openshift-bot and GitHub seem overly touchy about that, because git itself made no complaints about conflicts during the rebase. Anyhow, this will need another /lgtm, @yifan-gu.

[yifan-gu]

/lgtm

[openshift-ci-robot]

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