Fix debugscript setting to 0 when using invalid characters (#1602)

Author: Unde-R

Server/mods/deathmatch/logic/CConsoleCommands.cpp

@@ -1234,6 +1234,11 @@ bool CConsoleCommands::DebugScript(CConsole* pConsole, const char* szArguments,
 
             // Convert to number
             int iLevel = atoi(szArguments);
+            if (iLevel == 0 && strcmp(szArguments, "0") != 0)
+            {
+                pEchoClient->SendEcho("debugscript: Syntax is 'debugscript <mode>'");
+                return false;
+            }
             if (iLevel != (int)pPlayer->GetScriptDebugLevel())
             {
                 // Between 0 and 3?