Bug#260696: dpkg: say "make a subshell" instead of "background this process"

[Dan Jacobson <jidanni@jidanni.org>]

Package: dpkg
Version: 1.10.22
Severity: minor

     Configuration file `/etc/updatedb.conf'
      ==> Modified (by you or by a script) since installation.
      ==> Package distributor has shipped an updated version.
	What would you like to do about it ?  Your options are:
	 Y or I  : install the package maintainer's version
	 N or O  : keep your currently-installed version
	   D     : show the differences between the versions
	   Z     : background this process to examine the situation


Say "make a subshell" instead of "background this process", so as to
reflect what you indeed do.

      The default action is to keep your current version.
     *** updatedb.conf (Y/I/N/O/D/Z) [default=N] ?

Also don't show the user capital letters if the lowercase versions work.