fixed for app locking issues

[jpappa200]

Currently the file locking is not working correctly and will only pause for one second and then continue. This allows for multiply instances t3c-apply to run at one time. This change will prevent that and log when retries when attempting to get application lock.

---

Which Traffic Control components are affected by this PR?

• Traffic Control Cache Config (t3c, formerly ORT)

What is the best way to verify this PR?

The best way to test is to build t3c, install on a cache. Queue updates, and in 2 separate terminals kick off t3c at the same time. You should see one run ant the other waiting to get application lock.

If this is a bugfix, which Traffic Control versions contained the bug?

• 7.0.1 and before

PR submission checklist

• This PR has tests
• This PR has documentation
• This PR has a CHANGELOG.md entry
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

[codecov]

Codecov Report

Merging #7352 (941cfb2) into master (dad5772) will decrease coverage by 0.79%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #7352      +/-   ##
============================================
- Coverage     25.06%   24.27%   -0.79%     
  Complexity       98       98              
============================================
  Files           593      337     -256     
  Lines         73644    43097   -30547     
  Branches         90       90              
============================================
- Hits          18459    10463    -7996     
+ Misses        53434    31755   -21679     
+ Partials       1751      879     -872     

Flag	Coverage Δ
golib_unit	?
grove_unit	?
t3c_unit	?
traffic_monitor_unit	?
traffic_ops_unit	19.70% <ø> (ø)
traffic_stats_unit	?
unit_tests	19.70% <ø> (-2.90%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
cache-config/t3c-apply/t3c-apply.go
lib/go-util/net.go
grove/lru/lru.go
cache-config/t3cutil/toreq/torequtil/torequtil.go
grove/plugin/http_cacheinspector.go
lib/go-util/ptr.go
lib/go-atscfg/strategiesdotconfig.go
lib/go-atscfg/snidotyaml.go
grove/grove.go
traffic_monitor/config/staticappdata.go
... and 247 more

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[traeak]

These look good.