bug#13580: 24.2.92; regression in calc-convert-units

[Roland Winkler]

start emacs -Q
start Calc
type 'k K / eV RET u c

expected result: either Emacs will ask me 'New units:' (as with
                 Emacs 23) or something else meaningful,
                 allowing me to convert 'k K / eV' to the units
                 of my choice

actual result: Calc returns 'k K / eV' expression unmodified



In GNU Emacs 24.2.92.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.12.9)
 of 2013-01-10 on lukas
Windowing system distributor `The X.Org Foundation', version 11.0.10400090
System Description:     Ubuntu 8.04.4 LTS