gdi32: Fix a memory leak

[Andrew Talbot]

Changelog:
    gdi32: Fix a memory leak.

diff --git a/dlls/gdi32/painting.c b/dlls/gdi32/painting.c
index 1b8d6aa..3b3bce3 100644
--- a/dlls/gdi32/painting.c
+++ b/dlls/gdi32/painting.c
@@ -970,7 +970,7 @@ BOOL WINAPI PolyDraw(HDC hdc, const POIN
             Polyline(hdc, line_pts, num_pts);
 
         MoveToEx(hdc, line_pts[num_pts - 1].x, line_pts[num_pts - 1].y, NULL);
-
+        HeapFree(GetProcessHeap(), 0, line_pts);
         result = TRUE;
     }