.gitignore: sms.db-shm sbs.db-wal (when db is open)

Change-Id: I788ebf15a1569584dd2f158be901bc6e9f7de177
diff --git a/.gitignore b/.gitignore
index 9d48551..e77dfa7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,3 +20,5 @@
 *.d
 *.merged
 sms.db
+sms.db-shm
+sms.db-wal