Make output of set_time() failures to console only show when needed

Currently, any ValueError exception thrown by set_time() prints the error to the console. Since some boards can take a few seconds to acquire a time, this results in a lot of console spam such as the following: 
```_GET_TIME returned 0
_GET_TIME returned 0
_GET_TIME returned 0
_GET_TIME returned 0
_GET_TIME returned 0
_GET_TIME returned 0
etc...```

