Remove option to include ADS workspaces in reflectometry list.

Refs #10112.
Resolve merge conflict between #10112 and #10098.

Refs #10112.

Conflicts:
	Code/Mantid/scripts/Interface/ui/reflectometer/refl_gui.py
	Code/Mantid/scripts/Interface/ui/reflectometer/refl_options.py
	Code/Mantid/scripts/Interface/ui/reflectometer/refl_options_window.py
	Code/Mantid/scripts/Interface/ui/reflectometer/refl_options_window.ui
Correct a couple of lines missed during the merge conflict.

Refs #10112.
Merge remote-tracking branch 'origin/feature/10112_scrap_workspace_population'