fix compiler warning "suggest explicit braces to avoid ambiguous "else"

[-Wparentheses]" in net.cpp

src/net.cpp

@@ -1585,13 +1585,17 @@ void StartNode(void* parg)
     {
         vector<CNetAddr> vaddr;
         if (LookupHost(pszHostName, vaddr))
+        {
             BOOST_FOREACH (const CNetAddr &addr, vaddr)
+            {
                 if (!addr.IsLocal())
                 {
                     addrLocalHost.SetIP(addr);
                     break;
                 }
             }
+        }
+    }
 #else
     // Get local host ip
     struct ifaddrs* myaddrs;