modified:   ../sql-common/my_time.c

Moving the logic that mixes warnings of two kinds:
- those came from truncating garbage before the actual parsing of date/time
- those came during the actual parsing
from outside to inside of str_to_datetime_or_date_body().
This makes the caller code easier and removes some code duplication.
We'll be adding more parsing functions for time intervals soon,
so this change helps to avoid more duplicate code in the coming functions.