Fixed #796 (**:**:** as time), which happens if the race is aborted

before a kart has moved (due to a division by zero). Now 99:59:00
is displayed instead, but in case that there should be other 
circumstances that trigger this problem, use 99:59:99 instead of
**:**:**.


git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@12055 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/modes/linear_world.cpp

@@ -546,6 +546,10 @@ float LinearWorld::estimateFinishTimeForKart(AbstractKart* kart)
     // Finish time is the time needed for the whole race with
     // the computed average speed computed.
     const float average_speed = kart_info.m_overall_distance/getTime();
+    // Avoid NAN as results when average_speed is low
+    // Instead just set time to 99:59:00
+    if(average_speed<0.1f)
+        return 99*60+59;
     return getTime() + (full_distance - kart_info.m_overall_distance)  
                      / average_speed;
 

src/utils/string_utils.cpp

@@ -471,8 +471,8 @@ namespace StringUtils
         // and an incorrect finishing time is estimated.
         if(int_time<0)
             return std::string("00:00:00");
-        else if(int_time >= 10000*60)  // up to 9999:59.99
-            return std::string("**:**:**");
+        else if(int_time >= 10000*60)  // up to 99:59.99
+            return std::string("99:59:99");
 
         int min        = int_time / 6000;
         int sec        = (int_time-min*6000)/100;