Logging target must be explicitly defined.

Whether the log-file should be written to the filesystem or to
shared memory must now be explicitly defined when calling
skygw_logmanager_init() (instead of passing that via the argc/argv
construct).

Also, the meaning of '-l' when invoking maxscale has been changed.

Earlier -l [file|shm] specified whether the trace and debug logs
should be written to shared memory (while the error and message
logs always were written to the filesystem) and the _default_
was to write them to shared memory.

Now, with only one file, '-l' has still the same meaning, but it
decides whether the one and only logfile should be written to shared
memory, or the filesystem and the _default_ is to write it to the
filesystem.

server/modules/routing/binlog/test/testbinlog.c

@@ -101,7 +101,7 @@ int main(int argc, char **argv) {
 
 	arg_vector[0] = "logmanager";
 	arg_vector[1] = NULL;
-	skygw_logmanager_init(NULL, arg_count,arg_vector);
+	skygw_logmanager_init(NULL, LOG_TARGET_DEFAULT, arg_count,arg_vector);
 	free(arg_vector);
 
 	skygw_log_disable(LOGFILE_DEBUG);