Added code to test if git hash is availible

apps/openmw/mwgui/mainmenu.cpp

@@ -23,12 +23,20 @@ namespace MWGui
         , mSaveGameDialog(NULL)
     {
         getWidget(mVersionText, "VersionText");
-        std::string rev =  OPENMW_VERSION_COMMITHASH;
-        rev = rev.substr(0,10);
         std::stringstream sstream;
-        sstream << "OpenMW version: " << OPENMW_VERSION << "\nrevision: " <<  rev;
+        sstream << "OpenMW version: " << OPENMW_VERSION;
+
+        // adding info about git hash if availible
+        std::string rev = OPENMW_VERSION_COMMITHASH;
+        std::string tag = OPENMW_VERSION_TAGHASH;
+        if (!rev.empty() && !tag.empty())
+        {
+                rev = rev.substr(0,10);
+                sstream << "\nrevision: " <<  rev;
+        }
+        
         std::string output = sstream.str();
-        mVersionText->setCaptionWithReplacing(output);
+        mVersionText->setCaption(output);
 
         updateMenu();
     }