[feature-wisun] RADIUS shared secret .json parameter set correction

[mikaleppanen]

Summary of changes

This pull request corrects configuration error that occurs if WisunBorderRouter class is created before Nanostack mesh system (especially dynamic memory system) is initialized by calling mesh_system_init(). On that situation, Nanostack cannot yet store the .json configuration for RADIUS shared secret and WisunBorderRouter has to do it. Without the correction, RADIUS shared secret and address are not configured correctly from .json configuration and RADIUS interface is not taken into use.

Impact of changes

None

Migration actions required

None

Documentation

None

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Pull request type

[X] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[] No Tests required for this change (E.g docs only update)
[X] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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Reviewers

@mikter @artokin

[ciarmcom]

@mikaleppanen, thank you for your changes.
@mikter @artokin @ARMmbed/mbed-os-maintainers please review.

[0xc0170]

Please review astyle failures

[mikaleppanen]

@0xc0170 astyle corrected, this can be tested on ci.

[0xc0170]

CI started

[mbed-ci]

Test run: SUCCESS

Summary: 11 of 11 test jobs passed
Build number : 1
Build artifacts