[submodule]: update sonic-utilities (#2150)

* 6d00d14 2018-10-13 | pfcwd cmd check (#342) (HEAD, origin/master, origin/HEAD) [Wenda Ni]
* eb92560 2018-10-12 | [show] Refactor show vlan brief to use configdb and update the output (#340) [Deva Nandhagopal]
* 9a139ab 2018-10-10 | Remove explicit dependency on tabulate; Add comments (#336) [Joe LeVeque]
* 7874b8f 2018-10-09 | Update restart_count to restore_count for warm restart (#326) [Jipan Yang]
* 7a51a85 2018-10-08 | [acl_loader] fix show acl table  (#329) [ironjosh]
* 54ebfc8 2018-10-05 | Add a "-l/--load-sysinfo" option for "config reload" to merge the system info on device (#324) [zhenggen-xu]
* 34810df 2018-10-05 | [show] Eliminate need for writing template files for 'show platform summary' and 'show version' (#335) [Joe LeVeque]
* 4258287 2018-10-05 | Added argument forwarder for platform reboot. (#333) [Nazarii Hnydyn]
* e2b4bd5 2018-10-03 | Warm reboot: Add support for docker upgrade (#292) [Jipan Yang]
* f1236aa 2018-10-01 | Root priviliege for ecn configuration set commands (#332) [Wenda Ni]
* 3098b8a 2018-10-01 | require root privilege for all pfcwd configuration commands (#330) [lguohan]
* 7627d08 2018-09-27 | [config]: Add portchannel related commands (#328) [Shuotian Cheng]
* b8a62d7 2018-09-27 | Add 'alias mode' support for show commands (#298) [paavaanan]
* 4383300 2018-09-26 | [aclshow]: Fix the KeyError issue in aclshow (#325) [Shuotian Cheng]

Signed-off-by: Guohan Lu <gulv@microsoft.com>