[trivial] Reuse translation and cleanup DEFAULT_* values

* DEFAULT_DISABLE_SAFEMODE = false
* Use DEFAULT_* constants for extern bools

src/netbase.h

@@ -19,8 +19,10 @@
 extern int nConnectTimeout;
 extern bool fNameLookup;
 
-/** -timeout default */
+//! -timeout default
 static const int DEFAULT_CONNECT_TIMEOUT = 5000;
+//! -dns default
+static const int DEFAULT_NAME_LOOKUP = true;
 
 #ifdef WIN32
 // In MSVC, this is defined as a macro, undefine it to prevent a compile and link error