logger: allow to log using tcp transport protocol

logger: allow to log using tcp transport protocol

This commit fixes error in usage() text, which claimed TCP is default
transport protocol.  That was not true, and neither it should be.  The
syslog messages has traditionally sent using UDP.

For the logger remains using UDP as first transport, but if it fails a
TCP connection is attempted.  If an user wishes remote logging can be
forced to use either UDP or TCP.  The service port for UDP is familiar
'syslog', for TCP the port 'syslog-conn' seems like reasonable default.

[kzak@redhat.com: - rename myopenlog to unix_socket(),
                  - always reset st to -1]

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
Signed-off-by: Karel Zak <kzak@redhat.com>