speed up the function 'find_exec' a bit

[Christopher Faylor]

On Wed, Jun 02, 2004 at 10:50:19PM +0200, Christophe Jaillet wrote:
>Here is a small patch to speed up the function 'find_exec' a bit
>At the top of the function we have :
>
>    bool has_slash = strchr (name, '/');
>
>So there is no need to compute it again a few line latter.
>
>
>ChangeLog entry
>===============
>2004-06-02  Christophe Jaillet <christophe.jaillet@wanadoo.fr>
>
> * spawn.cc: function 'find_exec'. Don't compute >>strchr (name, '/')<<
>twice

Applied with some stylistic changes and a new ChangeLog entry.

Thanks.
cgf