Bug 430179

Description of problem:
Once a command name has been resolved as being in a particular directory, bash fails to notice
insertion of a command of the same name in a directory earlier in the PATH.  It won't re-do its
search even if you hit it over the head by removing the previously found command.

Version-Release number of selected component (if applicable):
bash-3.2-19.fc8.x86_64

How reproducible:
100%

Steps to Reproduce:
[tgl@rh2 ~]$ cd
[tgl@rh2 ~]$ PATH=$HOME/bin1:$HOME/bin2:$PATH
[tgl@rh2 ~]$ export PATH
[tgl@rh2 ~]$ mkdir ~/bin2
[tgl@rh2 ~]$ cat >~/bin2/myscript
#! /bin/sh
echo "I am bin2/myscript"
[tgl@rh2 ~]$ chmod +x ~/bin2/myscript
[tgl@rh2 ~]$ myscript
I am bin2/myscript
[tgl@rh2 ~]$ which myscript
~/bin2/myscript
[tgl@rh2 ~]$ mkdir ~/bin1
[tgl@rh2 ~]$ cat >~/bin1/myscript
#! /bin/sh
echo "I am bin1/myscript"
[tgl@rh2 ~]$ chmod +x ~/bin1/myscript
[tgl@rh2 ~]$ myscript
I am bin2/myscript
[tgl@rh2 ~]$ which myscript
~/bin1/myscript
[tgl@rh2 ~]$ mv bin2/myscript bin2/myscript.x
[tgl@rh2 ~]$ myscript
-bash: /home/tgl/bin2/myscript: No such file or directory
[tgl@rh2 ~]$ which myscript
~/bin1/myscript

Actual results:
As above

Expected results:
I expect bash to discard cached command locations anytime there is a change in the
directories in PATH.  I'm fairly sure this used to work correctly in FC6.

Additional info: