package/neardal: unconditionally use libedit

neardal is licensed under LGPL-2.0, which is (most likely) not license
compatible with readline (GPL-3.0+), so always use the libedit backend.

The choice is done by ./configure, which first checks for libedit, and
uses readline only as a fallback. Since we do build libedit before
neardal, that's what is going to be picked up.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
[yann.morin.1998@free.fr:
  - add blurb about preference in ./configure
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>