MINIFICPP-1357 - Fix proxy port reading of InvokeHTTP
MINIFICPP-1357 - Fix proxy port reading of InvokeHTTP

Signed-off-by: Arpad Boda <aboda@apache.org>

This closes #899

dtrodrigues/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp