Improve code coverage for QuestionTypesService.java

[Ielay]

• test method "find(Id)"
• test method "find(Id, QuestionTypesOptions)"
• test method "findAll()"
• test method "findAll(QuestionTypesOptions)"

[coveralls]

Coverage increased (+0.4%) to 65.261% when pulling c3ef498 on Ielay:feature-216 into bb5077f on malinink:dev.

[coveralls]

Coverage increased (+0.4%) to 65.298% when pulling a784fbf on Ielay:feature-216 into bb5077f on malinink:dev.

[coveralls]

Coverage increased (+0.7%) to 65.557% when pulling 09f8d8f on Ielay:feature-216 into bb5077f on malinink:dev.

[Ielay]

Only one method left. It unused in this class and have an private access modifier.

[coveralls]

Coverage increased (+0.8%) to 65.668% when pulling 3ba2807 on Ielay:feature-216 into bb5077f on malinink:dev.