EMACS env. var check breaks new windows from emacs

[Jonathan Kamens]

The bash CHANGES file includes this change for 2.05b:

b.  Note that we're running under Emacs and disable line editing if
    $EMACS == `t'.

And, indeed, examination of the bash source code confirms this
behavior.

The problem with this change is that with it in place, if I type
"xterm &" from an Emacs shell window, the shell in the xterm window
that starts up has command-line editing disabled.  Ugh.

Suggestion: Only disable command-line editing if EMACS is set to 't'
*and* TERM is set to "dumb", which is what Emacs sets it to.

  Jonathan Kamens