remove TODO from the addAttribute() method on the files concept.jav, …

[fanyui]

TRUNK-4923

Description

Remove TODO from the addAttribute() method on the files concept.java, BaseCustomizableData.java, BaseCustomizableMetadata.java"

Related Issue

see https://issues.openmrs.org/browse/TRUNK-4923

Checklist:

• My pull request only contains one single commit.
• My pull request is based on the latest master branch
  git pull --rebase upstream master.
• I ran mvn clean package right before creating this pull request and
  added all formatting changes to my commit.
• My code follows the code style of this project.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

…BaseCustomizableData.java,BaseCustomizableMetadata.java

[mention-bot]

@fanyui, thanks for your PR! By analyzing the history of the files in this pull request, we identified @bmamlin, @chethandeshpande and @suniala to be potential reviewers.

[coveralls]

Coverage decreased (-0.02%) to 55.706% when pulling 5afe354 on fanyui:TRUNCK-4923 into 4dc0e2c on openmrs:master.