smscb: Ignore the very simple test application.
diff --git a/.gitignore b/.gitignore
index 455440f..d39ae4a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -29,3 +29,4 @@
 tests/timer/timer_test
 tests/msgfile/msgfile_test
 tests/ussd/ussd_test
+tests/smscb/smscb_test