net: narrow include scope after moving to netaddress

Net functionality is no longer needed for CAddress/CAddrman/etc. now that
CNetAddr/CService/CSubNet are dumb storage classes.

src/test/net_tests.cpp

@@ -9,6 +9,7 @@
 #include "serialize.h"
 #include "streams.h"
 #include "net.h"
+#include "netbase.h"
 #include "chainparams.h"
 
 using namespace std;