sms: Add a simple SystemTap probe to see SQL queries

This will proble all queries done in the system. This can
help to identify some issues with libdbi's performance.

openbsc/contrib/sms/sqlite-probe.tap.d

@@ -0,0 +1,5 @@
+probe process("/usr/lib/libsqlite3.so.0.8.6").function("sqlite3_get_table")
+{
+  a = user_string($zSql);
+  printf("sqlite3_get_table called '%s'\n", a);
+}