Fix hostmask cloaking bug, don't cloak multiple times

Previously, each server would cloak every user's hostmask. The problem
is that if a network has more than one server, then a user's hostmask
would get cloaked twice. This patch ensures that a server only cloaks
the hostmask if it has not yet been cloaked (the period indicates it's
still an IP address).

Closes #228.

src/ngircd/client.c

@@ -337,7 +337,9 @@ Client_SetHostname( CLIENT *Client, const char *Hostname )
 	assert(Client != NULL);
 	assert(Hostname != NULL);
 
-	if (Conf_CloakHost[0]) {
+	/* Only cloak the hostmask if it has not yet been cloaked (the period
+	 * indicates it's still an IP address). */
+	if (Conf_CloakHost[0] && strchr(Client->host, '.')) {
 		char cloak[GETID_LEN];
 
 		strlcpy(cloak, Hostname, GETID_LEN);