Add Android interface set Display pin callback server API to

Add Android interface set Display pin callback server API to
display for RANDOM_PIN provisioning.

[Patch #4] Added malloc failed check and Renaming of variable
           to be more consistent.
[Patch #5] Addressed Randeep's review comments and upated
           provisioning sample's build.gradle
[Patch #8] Addressed review comment.

Note: This change depends upon patch set #3047
      This can be cherry picked for 1.0.0-dev

Change-Id: If704a01a760ec0880ea6e1a89f7e856d2f1ba3e5
Signed-off-by: Sandeep Sharma <sandeep.s9@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/3193
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Sachin Agrawal <sachin.agrawal@intel.com>