[IOT-2251] Resolve getValue() & setValue() APIs for argument string, Attribute Value

[IOT-2251] Resolve getValue() & setValue() APIs for argument string, Attribute Value
getValue() & setValue() APIs returned "no matching function argument" while being callled with the argument: string, AttributeValue
Previously this worked fine, this problem is being generated because of the commit:
https://gerrit.iotivity.org/gerrit/#/c/19585

Change-Id: Ibcf7d6f1d7e65a32ee7113ddaec958ab8073aa07
Signed-off-by: Mushfiqu Islam Antu <i.mushfiq@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/19901
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>
Reviewed-by: Ashok Babu Channa <ashok.channa@samsung.com>