dirmngr: Rename file dns-cert.c.
* dirmngr/dns-cert.c: Rename to dirmngr/dns-stuff.c. * dirmngr/dns-cert.h: Rename to dirmngr/dns-stuff.h and change includers. * dirmngr/t-dns-cert.c: Rename to dirmngr/t-dns-stuff.c. * dirmngr/Makefile.am: Adjust.
- Signed-off-by: Werner Koch <wk@gnupg.org>