SCRUM: 'Replication: PURGE LOGS with date' task

Added:

PURGE [MASTER] LOGS BEFORE date/date_expression
expire-logs-days option
  With this option old files are deleted when
      - mysqld is started
      - log is rotated
      - someone does FLUSH LOGS






sql/lex.h:
  For PURGE LOGS BEFORE
sql/log.cc:
  Added purge_logs_before_date to MYSQL_LOG class
sql/mysql_priv.h:
  For startup option --expire-logs-days
sql/mysqld.cc:
  Added options expire-logs-days
  When mysqld is started old log files are deleted.
sql/sql_class.h:
  For PURGE LOGS BEFORE and expire-log-days option
sql/sql_lex.h:
  For PURGE LOGS BEFORE
sql/sql_parse.cc:
  Old logs are deleted
  when someone does FLUSH LOGS
sql/sql_repl.cc:
  For PURGE LOGS BEFORE and expire-log-days option
sql/sql_repl.h:
  For PURGE LOGS BEFORE and expire-log-days option
sql/sql_yacc.yy:
  For PURGE LOGS BEFORE

sql/sql_lex.h

@@ -64,7 +64,7 @@ enum enum_sql_command {
   SQLCOM_ROLLBACK, SQLCOM_COMMIT, SQLCOM_SLAVE_START, SQLCOM_SLAVE_STOP,
   SQLCOM_BEGIN, SQLCOM_LOAD_MASTER_TABLE, SQLCOM_CHANGE_MASTER,
   SQLCOM_RENAME_TABLE, SQLCOM_BACKUP_TABLE, SQLCOM_RESTORE_TABLE,
-  SQLCOM_RESET, SQLCOM_PURGE, SQLCOM_SHOW_BINLOGS,
+  SQLCOM_RESET, SQLCOM_PURGE, SQLCOM_PURGE_BEFORE, SQLCOM_SHOW_BINLOGS,
   SQLCOM_SHOW_OPEN_TABLES, SQLCOM_LOAD_MASTER_DATA,
   SQLCOM_HA_OPEN, SQLCOM_HA_CLOSE, SQLCOM_HA_READ,
   SQLCOM_SHOW_SLAVE_HOSTS, SQLCOM_DELETE_MULTI, SQLCOM_UPDATE_MULTI,
@@ -413,6 +413,7 @@ typedef struct st_lex
   char *length,*dec,*change,*name;
   char *backup_dir;				/* For RESTORE/BACKUP */
   char* to_log;                                 /* For PURGE MASTER LOGS TO */
+  time_t purge_time;                            /* For PURGE MASTER LOGS BEFORE */
   char* x509_subject,*x509_issuer,*ssl_cipher;
   char* found_colon;                            /* For multi queries - next query */
   enum SSL_type ssl_type;			/* defined in violite.h */