Hide the in-rietveld flag in the UI. It is only used only by tooling and shouldn...

Hide the in-rietveld flag in the UI.  It is only used only by tooling and shouldn't clutter the UI.
https://bugs.webkit.org/show_bug.cgi?id=39024

Reviewed by Ojan Vafai.

* template/en/custom/attachment/list.html.tmpl:
  Removes this flag entirely from the UI, not needed on this page.
* template/en/custom/flag/list.html.tmpl: Added.
  Copied from template/en/default/flag/list.html.tmpl with only changes inside the if WEBKIT_CHANGES section.
  Hides the flag rather than removing it completely, so tools can still interact with it.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@59271 268f45cc-cd09-0410-ab3c-d52691b4dbfc