FIX for: CCL isn't happy with ps::warn-deprecated

[Ben Hyde]

This code[1] doesn't work well in CCL.  Calls upon warn-deprecated play out as so:

ps> (warn-deprecated 'forth 'lisp)
0> Calling (warn-deprecated forth lisp) 
; Compiler warning: In a toplevel form: Nonspecific warning
; While executing: warn-deprecated, in process repl-thread(12).
<0 warn-deprecated returned nil
nil
ps> 

This can be resolved by adjusting the condition being defined:

ps> (define-condition simple-style-warning (simple-warning style-warning) ())
simple-style-warning
ps> (warn-deprecated 'forth 'lisp)
0> Calling (warn-deprecated forth lisp) 
; Compiler warning: FORTH is deprecated, use LISP instead
; While executing: warn-deprecated, in process repl-thread(12).
<0 warn-deprecated returned nil
nil
ps> 

WDYT?