[Bug-readline] Line width not adjusted after window resizes

[Carlos Pita]

Readline output line width is not correctly adjusted after window resizes.

In particular, this is a serious problem for people using tiling
windows managers, as completion output is close to unreadable after
window was shrunken.

This was already reported by someone else here:
   http://lists.gnu.org/archive/html/bug-readline/2014-07/msg00004.html

To reproduce:
  - open a terminal emulator window
  - run, say, ipython
  - type p and <tab> in order to autocomplete
  - now reduce the window width
  - type p and <tab> again and see how the ouput is ill formatted

Details:

  Linux 3.18.6-1-ARCH #1 SMP PREEMPT Sat Feb 7 08:44:05 CET 2015
x86_64 GNU/Linux
  readline 6.3.006-1