fix mysql clean on ubuntu
fix mysql clean on ubuntu

Closes-Bug: 1409902
Change-Id: I72900eb2c7f3c6f66d829b10e9bb73b6d186da98

pacinete/devstack,richliu/devstack,parul24/devstack,affo/devstack,mmasaki/devstack,pacinete/devstack,HPCHub/devstack,dirkmueller/devstack,CloudServer/devstack,kplus/devstack-moonshot,HPCHub/devstack,vsham20/devstack,nuxeh/devstack,noironetworks/devstack,bigswitch/devstack,samgoon/devstack,bswartz/devstack,upadhyay-prashant/devstack,openstack-dev/devstack,nuxeh/devstack,parul24/devstack,bq-xiao/devstack,bljgaurav/openstack-test,wenhuizhang/devstack,dtroyer/devstack,costingalan/devstack,liuquansheng47/devstack,BSJAIN92/OpenStack,pombredanne/devstack,CloudServer/devstack,dirkmueller/devstack,bigswitch/devstack,LoHChina/devstack,mc2014/devstack,TwinkleChawla/devstack,avvocatodemarchis/devstack,group-policy/devstack,prithivm/branch01,Mahito/devstack,sc68cal/devstack,andrewrothstein/devstack,pombredanne/devstack,richliu/devstack,andrewrothstein/devstack,BSJAIN92/OpenStack,bswartz/devstack,promptworks/devstack,mc2014/devstack,pczerkas/devstack,eharney/devstack,NaokiMiyata/devstack,atulpatil301/devstack,upadhyay-prashant/devstack,sequenceiq/devstack,neerja28/Devstack_GlusterFS,olivierlemasle/devstack,samgoon/devstack,sequenceiq/devstack,liuquansheng47/devstack,varunarya10/devstack,avvocatodemarchis/devstack,NaokiMiyata/devstack,nawawi/openstack,dtroyer/devstack,vsham20/devstack,olivierlemasle/devstack,vishnugonela/devstack,rushiagr/devstack,neerja28/Devstack_GlusterFS,group-policy/devstack,atulpatil301/devstack,promptworks/devstack,mssumanth/devstack,flavio-fernandes/devstack,noironetworks/devstack,bljgaurav/openstack-test,ozamiatin/devstack,costingalan/devstack,wenhuizhang/devstack,j4/devstack,kplus/devstack-moonshot,herrsechs/devstack,nawawi/openstack,eharney/devstack,varunarya10/devstack,rushiagr/devstack,thomasem/devstack,prithivm/branch01,openstack-dev/devstack,affo/devstack,herrsechs/devstack,ozamiatin/devstack,thomasem/devstack,Mahito/devstack,LoHChina/devstack,sc68cal/devstack,TwinkleChawla/devstack,j4/devstack,pczerkas/devstack,mssumanth/devstack,vishnugonela/devstack,mmasaki/devstack,flavio-fernandes/devstack,bq-xiao/devstack