Fix: set ptr to NULL to suppress old gcc warnings

Fix: set ptr to NULL to suppress old gcc warnings

This has been seen with gcc 4.4.5 on a 32 bit machine.

consumer.c: In function ‘consumer_add_relayd_socket’:
consumer.c:3002: warning: ‘relayd’ may be used uninitialized in this
function

However, the relayd pointer can not be used uninitialized so this patch
suppresses the warning.

Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>