Field_time::get_time() did not initialize some members of 
MYSQL_TIME which led to valgrind warnings when those members 
were accessed in Protocol_simple::store_time(). 
 
It is unlikely that this bug could result in wrong data 
being returned, since Field_time::get_time() initializes the 
'day' member of MYSQL_TIME to 0, so the value of 'day' 
in Protocol_simple::store_time() would be 0 regardless 
of the values for 'year' and 'month'.

mysql-test/r/type_time.result:
  Added a test case for bug #44792.
mysql-test/t/type_time.test:
  Added a test case for bug #44792.
sql/field.cc:
  Field_time::get_time() did not initialize some members of 
  MYSQL_TIME which led to valgrind warnings when those members 
  were accessed in Protocol_simple::store_time().