scd: move SCDaemon to libexecdir

[NIIBE Yutaka]

On 2013-03-29 at 09:01 +0100, Werner Koch wrote:
> On Fri, 29 Mar 2013 02:11, gniibe at fsij.org said:
> 
> > I think that SCDaemon should not be in bindir, since it is not expected
> > to be run as command line directly by any user (including developers who
> > test it).  When it's in bindir, it's just troublesome when user invokes
> > it by the command line.
> 
> You mean because scdaemon would than grab the reader and an instance
> started by gpg-agent won't be able to use the reader then?  I think this
> is a good reason to move it to libexec.

Yes, exactly.  Sorry that I wasn't clear.

I had a tutorial session for GnuPG and Gnuk Token the other day.

I explained the relationship of gpg, gpg-agent, scdaemon, and
pinentry. Then, I said that gpg-agent should be there (by login
procedure of Xsession, or something.  If not, invoke it).  I didn't
said how scdaemon is invoked and proceeded the tutorial.  But some
people thought that scdaemon should be there as well as gpg-daemon,
and invoke it by their command line interface.  Later, those people
said that "I can't access Gnuk Token!".  As I didn't expected people
invoked scdaemon manually, it took some time to realize the situation.

OK to apply?
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