nitb/ctrl: Add command to add/modify a subscriber to the database

The test has been manually verified. Executing the select for
the subscribers showed:

sqlite> select * from Subscriber;
1|2014-03-23 12:12:46|2014-03-23 12:19:09|2620345||445567|1||0|

This created a subscriber with the right IMSI, MSISDN and has
it authorized.

Fixes: SYS#275
diff --git a/openbsc/src/libmsc/Makefile.am b/openbsc/src/libmsc/Makefile.am
index 1e58cd1..24db2c2 100644
--- a/openbsc/src/libmsc/Makefile.am
+++ b/openbsc/src/libmsc/Makefile.am
@@ -17,7 +17,7 @@
 			ussd.c \
 			vty_interface_layer3.c \
 			transaction.c \
-			osmo_msc.c
+			osmo_msc.c ctrl_commands.c
 
 if BUILD_SMPP
 noinst_HEADERS = smpp_smsc.h