Update vertex count stats when drawing smooth lines (OGL) (#1932)

The statistics are updated in the generic codepath, which is not used by
RageDisplay_Legacy::DrawLineStripInternal() when rendering smooth lines.

Note, that the output vertex count can differ a lot between smooth lines
(2) and non-smooth lines (~38 output vertices per input vertex), so
updating the statistics can not be done in RageDisplay::DrawLineStrip()
like it is donw for the other draw functions.

src/RageDisplay_OGL.cpp

@@ -1617,6 +1617,7 @@ void RageDisplay_Legacy::DrawLineStripInternal( const RageSpriteVertex v[], int
 	/* Draw the line loop: */
 	SetupVertices( v, iNumVerts );
 	glDrawArrays( GL_LINE_STRIP, 0, iNumVerts );
+	StatsAddVerts(iNumVerts);
 
 	glDisable( GL_LINE_SMOOTH );
 
@@ -1642,6 +1643,7 @@ void RageDisplay_Legacy::DrawLineStripInternal( const RageSpriteVertex v[], int
 
 	SetupVertices( v, iNumVerts );
 	glDrawArrays( GL_POINTS, 0, iNumVerts );
+	StatsAddVerts(iNumVerts);
 
 	glDisable( GL_POINT_SMOOTH );
 }