bug#23248: 25.1.50; user option rectangle-preview is unused

[Mark Oteiza]

Hi,

The defcustom `rectangle-preview' in rect.el--for controlling whether the
preview is shown for C-x r t--is not used.

In GNU Emacs 25.1.50.1 (x86_64-unknown-linux-gnu, X toolkit, Xaw scroll bars)
 of 2016-03-20 built on logos
Repository revision: 5283593ced29a2c98e4af3607a68ee7a6d10fcac
Configured using:
 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --without-gconf --with-modules
 --with-x-toolkit=lucid 'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe
 -fstack-protector-strong --param=ssp-buffer-size=4 -g
 -fvar-tracking-assignments -g -fvar-tracking-assignments'
 CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro'