If a temporary error occured inside a group on an event that was not the first
event of the group, the slave could get stuck because the retry counter is reset
whenever an event was executed successfully.

This patch only reset the retry counter when an entire group has been successfully
executed, or failed with a non-transient error.


sql/slave.cc:
  Adding debug printouts to every place where Relay_log_info::trans_retries
  is changed and to has_temporary_error() to print the error when returning.
  
  Adding debug variable all_errors_are_temporary_errors to make all errors
  for slave thread temporary errors.
  
  Adding code so that the Relay_log_info::trans_retries is only reset when
  an entire group was sucessfully executed, or a non-temporary error occured.
mysql-test/suite/rpl/r/rpl_temporary_errors.result:
  New BitKeeper file ``mysql-test/suite/rpl/r/rpl_temporary_errors.result''
mysql-test/suite/rpl/t/rpl_temporary_errors-slave.opt:
  New BitKeeper file ``mysql-test/suite/rpl/t/rpl_temporary_errors-slave.opt''
mysql-test/suite/rpl/t/rpl_temporary_errors.test:
  New BitKeeper file ``mysql-test/suite/rpl/t/rpl_temporary_errors.test''