Fix the issue of an error printed when shutting down the IoT Server

[rasika]

Purpose

To fix the issue of an error printed when shutting down the IoT Server. Resolves https://github.com/wso2/product-iots/issues/1724.

Goals

To fix the issue of an error printed when shutting down the IoT Server

Approach

To fix the issue of an error printed when shutting down the IoT Server.

User stories

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Release note

Fix the issue of an error printed when shutting down the IoT Server

Documentation

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Training

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Certification

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Marketing

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Automation tests

• Unit tests

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• Integration tests

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Security checks

• Followed secure coding standards in http://wso2.com/technical-reports/wso2-secure-engineering-guidelines? yes
• Ran FindSecurityBugs plugin and verified report? yes
• Confirmed that this PR doesn't commit any keys, passwords, tokens, usernames, or other secrets? yes

Samples

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Related PRs

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Migrations (if applicable)

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Test environment

Apache Maven 3.5.2 Maven home: /usr/local/Cellar/maven/3.5.2/libexec Java version: 1.8.0_152, vendor: Oracle Corporation Java home: /Library/Java/JavaVirtualMachines/jdk1.8.0_152.jdk/Contents/Home/jre Default locale: en_LK, platform encoding: UTF-8 OS name: "mac os x", version: "10.13.3", arch: "x86_64", family: "mac"

Learning

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