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/Makefile.am b/src/Makefile.am
index 3e014ae..bb0bd56 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -4,5 +4,6 @@
 
 bin_PROGRAMS = osmo_pcap_client
 
-osmo_pcap_client_SOURCES = osmo_client_main.c osmo_common.c
+osmo_pcap_client_SOURCES = osmo_client_main.c osmo_common.c \
+			   osmo_client_core.c osmo_client_vty.c
 osmo_pcap_client_LDADD = $(PCAP_LIBS)