Plugins: Make open method clearer to use

This highlights that the FileHandler class can also be seen as a method
similar to open, and it removes unnecessary context managers, allowing
plugins to close files as they wish (they must, however, remember to
close the file for it to be committed).

volatility/framework/plugins/windows/modules.py

@@ -58,9 +58,10 @@ class Modules(interfaces.plugins.PluginInterface):
 
             file_output = "Disabled"
             if self.config['dump']:
-                file_handle = dlllist.DllList.dump_pe(self.context, pe_table_name, mod, self._file_handler)
+                file_handle = dlllist.DllList.dump_pe(self.context, pe_table_name, mod, self.open)
                 file_output = "Error outputting file"
                 if file_handle:
+                    file_handle.close()
                     file_output = file_handle.preferred_filename
 
             yield (0, (format_hints.Hex(mod.vol.offset), format_hints.Hex(mod.DllBase),