Fix compilation of UPNP support
Fix compilation of UPNP support

Miniupnpc stores its headers in a directory miniupnpc, which was missing
where the headers where included.

caraka/gridcoinresearch,Lederstrumpf/Gridcoin-Research,icede/Gridcoin-Research,caraka/gridcoinresearch,fooforever/Gridcoin-Research,fooforever/Gridcoin-Research,fooforever/Gridcoin-Research,icede/Gridcoin-Research,fooforever/Gridcoin-Research,caraka/gridcoinresearch,icede/Gridcoin-Research,Lederstrumpf/Gridcoin-Research,theMarix/Gridcoin-Research,gridcoin/Gridcoin-Research,theMarix/Gridcoin-Research,gridcoin/Gridcoin-Research,caraka/gridcoinresearch,caraka/gridcoinresearch,icede/Gridcoin-Research,caraka/gridcoinresearch,tomasbrod/Gridcoin-Research,fooforever/Gridcoin-Research,Git-Jiro/Gridcoin-Research,Git-Jiro/Gridcoin-Research,fooforever/Gridcoin-Research,TheCharlatan/Gridcoin-Research,gridcoin/Gridcoin-Research,tomasbrod/Gridcoin-Research,Lederstrumpf/Gridcoin-Research,Git-Jiro/Gridcoin-Research,Lederstrumpf/Gridcoin-Research,icede/Gridcoin-Research,gridcoin/Gridcoin-Research,icede/Gridcoin-Research,gridcoin/Gridcoin-Research,tomasbrod/Gridcoin-Research,theMarix/Gridcoin-Research,TheCharlatan/Gridcoin-Research,Lederstrumpf/Gridcoin-Research,theMarix/Gridcoin-Research,TheCharlatan/Gridcoin-Research,tomasbrod/Gridcoin-Research,Git-Jiro/Gridcoin-Research,Git-Jiro/Gridcoin-Research,icede/Gridcoin-Research,tomasbrod/Gridcoin-Research,theMarix/Gridcoin-Research,TheCharlatan/Gridcoin-Research,TheCharlatan/Gridcoin-Research,theMarix/Gridcoin-Research,gridcoin/Gridcoin-Research,Lederstrumpf/Gridcoin-Research