stack/samples: Removing /W4 warnings.

stack/samples: Removing /W4 warnings.

Removing variable shadowing warnings: there were a few
variables using the same name in one scope and thus one
overwritten the other.

Bug: https://jira.iotivity.org/browse/IOT-1583

Change-Id: I9b20da2c4ebea8bdb4bbc3b64c7d308060bf258e
Signed-off-by: Pawel Winogrodzki <pawelwi@microsoft.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/20735
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Ziran Sun <ziran.sun@samsung.com>