[#19226] (2.5) blender uses deprecated 'strstream' STL class, causes warnings with gcc

thanks to Mauro Toffanin (equilibrium)

This is the only place where strstream were used.

source/gameengine/VideoTexture/Exception.cpp

@@ -21,7 +21,7 @@ http://www.gnu.org/copyleft/lesser.txt.
 */
 
 
-#include <strstream>
+#include <sstream>
 #include <fstream>
 
 #include <PyObjectPlus.h>
@@ -170,11 +170,11 @@ void Exception::setXptDesc (void)
 		// length of result code
 		const size_t rsltSize = 11;
 		// delimit description
-		const char delimRslt[] = ": ";
+		//const char delimRslt[] = ": ";
 		// set text of description
 		char rsltTxt[rsltSize];
-		std::ostrstream os(rsltTxt, rsltSize);
-		os << std::hex << m_hRslt << delimRslt << '\0';
+		std::ostringstream os;
+		os << std::hex << m_hRslt << ": " << '\0';
 		// copy result to description
 		m_desc.insert(0, rsltTxt);
 		// copy exception description to last exception string