MINIFICPP-885: Minor change to remove warning
MINIFICPP-885: Minor change to remove warning

This closes #575.

Signed-off-by: Marc Parisi <3cd89688bb0a35b1f4229ca5a98e5d7bf31861da@apache.org>

jdye64/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp,phrocker/nifi-minifi-cpp,phrocker/nifi-minifi-cpp,jdye64/nifi-minifi-cpp,phrocker/nifi-minifi-cpp,apiri/nifi-minifi-cpp,jdye64/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp,apiri/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp,apiri/nifi-minifi-cpp,phrocker/nifi-minifi-cpp,apiri/nifi-minifi-cpp,jdye64/nifi-minifi-cpp,jdye64/nifi-minifi-cpp,apiri/nifi-minifi-cpp,achristianson/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp,achristianson/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp,phrocker/nifi-minifi-cpp,achristianson/nifi-minifi-cpp,achristianson/nifi-minifi-cpp