Clang-tidy, fix bugprone-exception-escape.

Remove redundant call to `ofstream::close()` from `~PSStrokeRenderer`
and `~TextStrokeRenderer`. ofstream will be destructed automatically.

- For `~Depsgraph`, `std::function`'s constructor can throw.
- Passing throwing statements in the lambda will not be detected by
  clang-tidy.
Fix these issues by using lambda as function argument.

Reviewed By: sergey, sybren
Differential Revision: https://developer.blender.org/D9497

source/blender/freestyle/intern/stroke/TextStrokeRenderer.h

@@ -53,15 +53,11 @@ namespace Freestyle {
 class TextStrokeRenderer : public StrokeRenderer {
  public:
   TextStrokeRenderer(const char *iFileName = NULL);
-  virtual ~TextStrokeRenderer();
 
   /*! Renders a stroke rep */
   virtual void RenderStrokeRep(StrokeRep *iStrokeRep) const;
   virtual void RenderStrokeRepBasic(StrokeRep *iStrokeRep) const;
 
-  /*! Closes the output file */
-  void Close();
-
  protected:
   mutable ofstream _ofstream;
 };