Fix TO atscfg missing max origin conns

[rob05c]

Fixes a misordered SQL scan, which caused the Server Status to be
missing, causing the config gen to think there were no online servers,
and thus not create the max_origin_connections entry.

Note this is only in the old TO endpoints, not the config generator. The atstccfg generator doesn't have this issue.

• This PR is not related to any other Issue

Includes TO API (Integration) tests.
No docs, no interface change.
No changelog, no interface change.

Which Traffic Control components are affected by this PR?

• Traffic Ops

What is the best way to verify this PR?

Run TO API Tests.
Set Max Origin Connections on a DS, request the header rewrite endpoint for that DS, verify it includes a max_origin_connections entry.

If this is a bug fix, what versions of Traffic Control are affected?

• master
• 4.0.0 RC2

The following criteria are ALL met by this PR

• This PR includes tests OR I have explained why tests are unnecessary
• This PR includes documentation OR I have explained why documentation is unnecessary
• This PR includes an update to CHANGELOG.md OR such an update is not necessary
• This PR includes any and all required license headers
• This PR ensures that database migration sequence is correct OR this PR does not include a database migration
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

Additional Information

[mitchell852]

When i set max origin conns > 0 for delivery services that do NOT employ the mid-tier (i.e. DNS_LIVE) this looks good. When I call GET api/1.4/cdns/cdn-name/configfiles/ats/hdr_rw_xml-id.config, I see the following:

# DO NOT EDIT - Generated for cdn-name by Traffic Ops (https://trafficops.domain.net/) on Tue Jan 28 15:40:07 UTC 2020
cond %{REMAP_PSEUDO_HOOK}
set-config proxy.config.http.origin_max_connections 1000 [L]

But when i set max origin conns > 0 for delivery services that DO employ the mid-tier (i.e. DNS), I am not seeing an entry in any of the hdr_rw_mid_xml-id.config files.

[rob05c]

@mitchell852 Ah, the Mid query had the same bug. I fixed that too, both bugs should be fixed now.

[mitchell852]

I tested delivery services that employ the mid-tier and ones that do not and set max origin conns to >0 and 0 and saw the appropriate entry in hdr_rw_xml-id.config or hdr_rw_mid_xml-id.config using the following apis:

GET /api/1.4/cdns/cdn-name/configfiles/ats/hdr_rw_mid_xml-id.config
GET /api/1.4/cdns/cdn-name/configfiles/ats/hdr_rw_xml-id.config

I also checked that the location params were created and assigned to the appropriate profiles.

All TO API tests passed as well.

[mitchell852]

@rob05c - reminder to backport this to 4.0.x branch

[mhoppa]

FWIW I am getting some API test failures since this merged

hdr_rw_dot_config_test.go:110: expected 6 lines in the config (actual = 8)
hdr_rw_dot_config_test.go:90: expected 6 lines in the config (actual = 8)

@rob05c would you mind taking a look? or just run them and reconfirm that yours passed and mine should too :)