This update fixes the following issues for percona-toolkit:
- bnc#804102: update to 2.1.9:
* pt-heartbeat 2.1.8 doesn't use precision/sub-second timestamps
* pt-heartbeat 2.1.8 reports big time drift with UTC_TIMESTAMP
* pt-online-schema-change fails with "Duplicate entry" on MariaDB
* pt-online-schema-change makes bad DELETE trigger if PK is re-created with new columns
* pt-pmp doesn't list the origin lib for each function
* pt-query-digest shouldn't print "Error: none" for tcpdump
* pt-query-digest fails to parse non-SQL errors
* pt-table-checksum: Confusing error message with binlog_format ROW or MIXED on slave
* pt-table-sync false-positive error "Cannot nibble table because MySQL chose no index instead of the PRIMARY index"
* pt-stalk is too verbose, fills up log