Description of problem:
I have several commands mapped to Meta-whatever, and in the last day or so
the Meta is apparently no longer being passed to readline for command line
editing.  My prefered bind mode is emacs, and this has worked 4eva :)

Version-Release number of selected component (if applicable):
GNU bash, version 4.2.20(1)-release (x86_64-redhat-linux-gnu)

How reproducible:
100%

Steps to Reproduce:
1. add a bash binding that uses Alt as meta, e.g., bind '"\M-b": backward-word' 
2. command line "this is a multiword string"
                                           ^ point
3. press Alt-b to move back a word from the end of the line
  
Actual results:
"this is a multiword stringb"
                            ^

The 'b' is seen without the meta modifier and is inserted at point instead of moving point back.

Expected results:
"this is a multiword stringb"
                     ^ point should be on the start of the last word


Additional info:
The original alternate is to use Esc-b, which still works, along with Ctrl-LeftArrow, which also still works.  Just the Alt-KEY version fails.