Fix gonext command and do it random

Commit fixes broken "gonext" command, among other things reading time
from maprot, and it does random result of this command.
It also removes get_next() function, because it messes up the maprot,
so shouldn't be used.

source/src/server.cpp

@@ -3458,12 +3458,13 @@ void process(ENetPacket *packet, int sender, int chan)
                         time = min(time, 60);
                         if (vi->gonext)
                         {
-                            int ccs = mode ? maprot.next(false,false) : maprot.get_next();
+                            int ccs = rnd(maprot.configsets.length());
                             configset *c = maprot.get(ccs);
                             if(c)
                             {
                                 strcpy(vi->text,c->mapname);
                                 mode = vi->num1 = c->mode;
+                                time = vi->num2 = c->time;
                             }
                             else fatal("unable to get next map in maprot");
                         }

source/src/serverfiles.h

@@ -398,18 +398,6 @@ struct servermaprot : serverconfigfile
 
     configset *current() { return configsets.inrange(curcfgset) ? &configsets[curcfgset] : NULL; }
     configset *get(int ccs) { return configsets.inrange(ccs) ? &configsets[ccs] : NULL; }
-    int get_next()
-    {
-        int ccs = curcfgset;
-        while(!strcmp(configsets[curcfgset].mapname,configsets[ccs].mapname))
-        {
-            ccs++;
-            if(!configsets.inrange(ccs)) ccs=0;
-            if (ccs == curcfgset) break;
-        }
-        curcfgset = ccs;
-        return ccs;
-    }
 };
 
 // serverblacklist.cfg