osmo-pcap-client: Work on the client code, be able to open the device

Add vty code to allow changing the device, this will just attempt
to open and close the device. Nothing else is done.
diff --git a/src/osmo_client_main.c b/src/osmo_client_main.c
index f00530e..96f01ee 100644
--- a/src/osmo_client_main.c
+++ b/src/osmo_client_main.c
@@ -21,6 +21,7 @@
  */
 
 #include <osmo-pcap/common.h>
+#include <osmo-pcap/osmo_pcap_client.h>
 
 #include <osmocom/core/application.h>
 #include <osmocom/core/process.h>
@@ -46,6 +47,7 @@
 static int daemonize = 0;
 
 void *tall_bsc_ctx;
+struct osmo_pcap_client *pcap_client;
 extern void *tall_msgb_ctx;
 extern void *tall_ctr_ctx;
 
@@ -177,6 +179,14 @@
 
 	telnet_init(tall_bsc_ctx, NULL, 4240);
 
+	pcap_client = talloc_zero(tall_bsc_ctx, struct osmo_pcap_client);
+	if (!pcap_client) {
+		LOGP(DCLIENT, LOGL_ERROR, "Failed to allocate osmo_pcap_client.\n");
+		exit(1);
+	}
+	pcap_client->fd.fd = -1;
+	vty_client_init(pcap_client);
+
 	if (daemonize) {
 		rc = osmo_daemonize();
 		if (rc < 0) {