w32: Do no use Registry item DefaultLogFile for the main tools.

* g10/gpg.c (main): Set LOG_NO_REGISTRY.
* sm/gpgsm.c (main): Ditto.
* tools/gpg-connect-agent.c (main): Ditto.
* tools/gpgconf.c (main): Ditto.
(show_other_registry_entries): Print "DefaultLogFile".

The intention of this mostly forgotten registry entry was to allow for
easy debugging of the tools. However, with the global config file
common.conf things are anyway better. We disable the use for the
commonly used tools so that it does not look like calling gpg on the
command line seems to block with no output if the log
server (e.g. tcp://1.2.3.4:11111) is not reachable.