check openflow version before matching tcp_flags

tcp_flags are only supported after openflow 1.5 as seen at B.18.7 of openflow spec 1.5.0

src/main/java/net/floodlightcontroller/forwarding/Forwarding.java

@@ -596,7 +596,7 @@ public class Forwarding extends ForwardingBase implements IFloodlightModule, IOF
                     if (FLOWMOD_DEFAULT_MATCH_TRANSPORT_DST) {
                         mb.setExact(MatchField.TCP_DST, tcp.getDestinationPort());
                     }
-                    if(
+                    if(sw.getOFFactory().getVersion().compareTo(OFVersion.OF_15) >= 0 &&
                     sw.getSwitchDescription().getHardwareDescription().toLowerCase().contains("open vswitch") && (
                     Integer.parseInt(sw.getSwitchDescription().getSoftwareDescription().toLowerCase().split("\\.")[0]) > 2  || (
                     Integer.parseInt(sw.getSwitchDescription().getSoftwareDescription().toLowerCase().split("\\.")[0]) == 2 &&