python27: Remove patches/patch-ah (no longer needed)

Since Python 2.7.15 patches/patch-ah is no longer needed and badly interfere
(e.g. with it `curses.KEY_*' are no longer exposed):

- Prototypes of NetBSD curses(3) are as described, no need to patch them
- Avoid {lines,columns} -> {nlines,columns} rename, they are properly
  undef-ed due HAVE_TERM_H.
- Use keyname() (it should be present since NetBSD 2.0)

Bump PKGREVISION for devel/py-curses so it will be properly rebuild.

Fixes PR pkg/53330 reported by <oster>.

(leot)