Allow empty array in OCRepPayloadSetIntArray

Allow empty array in OCRepPayloadSetIntArray

[IOT-2458] OCRepPayloadSetIntArray() did not allow empty
array.  Fixed by not returning false when dimTotal is 0
and instead letting the function to get executed when input
array is NULL & dimTotal is 0.

Also fixed the usage of API in easy setup enrollee code.
Now using OCRepPayloadSetIntArrayAsOwner() instead of
OCRepPayloadSetIntArray() as the later duplicates the
memory which can be avoided "by giving payload ownership
to stack".

Added unit test in cbortests to test new API behavior.

Change-Id: If5352b1faf5a9355dd0f8a22882a6af545df6d29
Signed-off-by: Abhishek Pandey <abhi.siso@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/21591
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>
Reviewed-by: Todd Malsbary <todd.malsbary@intel.com>
Reviewed-by: Harish Marappa <h.marappa@samsung.com>
Reviewed-by: Ashok Babu Channa <ashok.channa@samsung.com>