ash,hush: share string

ash,hush: share string

function                                             old     new   delta
optschanged                                          133     139      +6
hush_main                                            997     982     -15
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 6/-15)              Total: -9 bytes
   text   data    bss    dec    hexfilename
 823160    445   7668 831273  caf29busybox_old
 823102    445   7668 831215  caeefbusybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>