Fix displaying LAN servers

LAN servers should be always visible, when user opens serverbrowser with
LAN servers only. And don't allow to switch from there to alternate views,
because for searchlan = 2 it doesn't make sense.

source/src/serverbrowser.cpp

@@ -879,6 +879,7 @@ const char *favcatcheck(serverinfo &si, const char *ckeys, char *autokeys = NULL
 
 void serverbrowseralternativeviews(int shiftdirection)
 {
+    if(searchlan == 2) return;
     const char *ckeys = getalias("serverbrowseraltviews");
     if(!ckeys) return;
     const char *sep = " \t\n\r";