Fixed a bug where sns tried to cd to a nonexistent store

src/main/stage1.sns.sh

@@ -11,7 +11,7 @@ elif [ "$1" != "-i" ]; then
      exit 5 #ERR_NO_STORE
 fi
 
-cd "$NOTES_DIR"
+if [ -d "$NOTES_DIR" ]; then cd "$NOTES_DIR"; fi
 if [ "$ENCRYPTION" == "TRUE" ]; then
     # If the user chose not to decrypt notes before, clear that preference.
     if [ -r "$NOTES_DIR"/.do_not_decrypt ]; then