Fix NPE if global setting implicit.host.tags is set to null

[harikrishna-patnala]

Description

This PR fixes the issue #8056

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• build/CI

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

How Has This Been Tested?

Followed the steps mentioned in the issue and did not face NPE after the fix

How did you try to break this feature and the system with this change?

[harikrishna-patnala]

@blueorangutan package

[blueorangutan]

@harikrishna-patnala a [SF] Jenkins job has been kicked to build packages. It will be bundled with KVM, XenServer and VMware SystemVM templates. I'll keep you posted as I make progress.

[weizhouapache]

code lgtm
tested ok

[DaanHoogland]

clgtm

[codecov]

Codecov Report

Merging #8066 (a0f941b) into 4.18 (29c7b31) will increase coverage by 0.04%.
Report is 71 commits behind head on 4.18.
The diff coverage is 18.70%.

@@             Coverage Diff              @@
##               4.18    #8066      +/-   ##
============================================
+ Coverage     13.02%   13.06%   +0.04%     
- Complexity     9032     9108      +76     
============================================
  Files          2720     2720              
  Lines        257080   257538     +458     
  Branches      40088    40156      +68     
============================================
+ Hits          33476    33659     +183     
- Misses       219400   219649     +249     
- Partials       4204     4230      +26     

Files	Coverage Δ
...hestration/service/VolumeOrchestrationService.java	100.00% <ø> (ø)
.../main/java/com/cloud/network/IpAddressManager.java	100.00% <100.00%> (ø)
...ava/com/cloud/network/as/AutoScaleVmProfileVO.java	80.20% <100.00%> (+11.66%)	⬆️
...java/com/cloud/upgrade/DatabaseUpgradeChecker.java	40.89% <100.00%> (+0.64%)	⬆️
...va/com/cloud/upgrade/DatabaseVersionHierarchy.java	85.10% <100.00%> (+1.01%)	⬆️
.../api/command/admin/ratelimit/ResetApiLimitCmd.java	0.00% <ø> (ø)
...oud/hypervisor/kvm/resource/LibvirtConnection.java	0.00% <ø> (ø)
.../hypervisor/kvm/storage/ScaleIOStorageAdaptor.java	10.44% <100.00%> (ø)
...ava/com/cloud/api/commands/StopNetScalerVMCmd.java	0.00% <ø> (ø)
...tungsten/api/command/ListTungstenFabricTagCmd.java	0.00% <ø> (ø)
... and 59 more

... and 7 files with indirect coverage changes

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[blueorangutan]

Packaging result [SF]: ✔️ el7 ✔️ el8 ✔️ el9 ✔️ debian ✔️ suse15. SL-JID 7310

[DaanHoogland]

@blueorangutan test

[blueorangutan]

@DaanHoogland a [SF] Trillian-Jenkins test job (centos7 mgmt + kvm-centos7) has been kicked to run smoke tests

[blueorangutan]

[SF] Trillian test result (tid-7909)
Environment: kvm-centos7 (x2), Advanced Networking with Mgmt server 7
Total time taken: 43470 seconds
Marvin logs: https://github.com/blueorangutan/acs-prs/releases/download/trillian/pr8066-t7909-kvm-centos7.zip
Smoke tests completed. 107 look OK, 1 have errors, 0 did not run
Only failed and skipped tests results shown below:

Test	Result	Time (s)	Test File
test_03_deploy_vm_wrong_checksum	Error	39.60	test_templates.py
test_09_list_templates_download_details	Failure	0.04	test_templates.py