package/cifs-utils: bump to version 6.9

package/cifs-utils: bump to version 6.9

>From https://wiki.samba.org/index.php/LinuxCIFS_utils:

- April 5, 2019: Release 6.9
  - smbinfo utility is added to query various kinds of information
    from the server (objectId, snapshots, different FileInfo* classes
    and other metadata)
  - server IP change is supported by expiring DNS key resolver entries
  - get/setcifsacl tools are improved to handle unexpected behavior
  - share snapshot are allowed to be specified by a GMT token or SMB
    100-nanoseconds time
  - various new mount option are documented: bsize, handletimeout,
    handlecache, rdma, max_credits and others
  - https://lists.samba.org/archive/samba-technical/2019-April/133233.html

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>