super small bug in opengl version query

was retuning the wrong version 5.5 was a giveaway that
something was wrong

Rendering/OpenGL2/vtkOpenGLRenderWindow.cxx

@@ -578,7 +578,7 @@ void vtkOpenGLRenderWindow::GetOpenGLVersion(int &major, int &minor)
 #endif
     }
 
-  major = glMinorVersion;
+  major = glMajorVersion;
   minor = glMinorVersion;
 }