[ingo] bashism in ingo procmail rules

[Julien Savoie]

ingo's procmail rules use "echo -e" which works fine under bash, but not
dash.  Fix is simple, use /bin/echo.  So I added this to backends.local.php

$backends['procmail']['transport'][Ingo::RULE_ALL]['params']['echo'] =
'/bin/echo';

I still see "echo" without the /bin/echo in .procmailrc scripts.  What
did I miss?  Does this belong in script rather than transport?  Reading
backends.php does not suggest this however.