Fix some description/grammar mistakes in messages
Fix some description/grammar mistakes in messages

Change message "Multiple filter actions is not " to
"Multiple filter actions are not "

Change message "You can only assign three column" to
"You can assign at most three columns"

Change message "You can only assign two columns" to
"You can assign at most two columns"

Change-Id: I343263fccf4f25381453b53630a13476d71bb775

FNST-OpenStack/horizon,yeming233/horizon,sandvine/horizon,gerrive/horizon,ChameleonCloud/horizon,davidcusatis/horizon,damien-dg/horizon,BiznetGIO/horizon,redhat-openstack/horizon,NeCTAR-RC/horizon,anthonydillon/horizon,idjaw/horizon,wolverineav/horizon,redhat-cip/horizon,bac/horizon,Mirantis/mos-horizon,maestro-hybrid-cloud/horizon,coreycb/horizon,dan1/horizon-x509,sandvine/horizon,maestro-hybrid-cloud/horizon,openstack/horizon,redhat-cip/horizon,redhat-openstack/horizon,bigswitch/horizon,gerrive/horizon,NeCTAR-RC/horizon,takeshineshiro/horizon,maestro-hybrid-cloud/horizon,damien-dg/horizon,Tesora/tesora-horizon,idjaw/horizon,philoniare/horizon,BiznetGIO/horizon,sandvine/horizon,FNST-OpenStack/horizon,bac/horizon,Dark-Hacker/horizon,idjaw/horizon,Tesora/tesora-horizon,coreycb/horizon,bigswitch/horizon,NeCTAR-RC/horizon,Dark-Hacker/horizon,takeshineshiro/horizon,wolverineav/horizon,saydulk/horizon,philoniare/horizon,yeming233/horizon,redhat-openstack/horizon,saydulk/horizon,noironetworks/horizon,takeshineshiro/horizon,FNST-OpenStack/horizon,anthonydillon/horizon,noironetworks/horizon,coreycb/horizon,noironetworks/horizon,Mirantis/mos-horizon,NeCTAR-RC/horizon,yeming233/horizon,bigswitch/horizon,redhat-openstack/horizon,django-leonardo/horizon,BiznetGIO/horizon,saydulk/horizon,davidcusatis/horizon,gerrive/horizon,philoniare/horizon,openstack/horizon,redhat-cip/horizon,sandvine/horizon,damien-dg/horizon,damien-dg/horizon,django-leonardo/horizon,django-leonardo/horizon,philoniare/horizon,davidcusatis/horizon,maestro-hybrid-cloud/horizon,Dark-Hacker/horizon,wolverineav/horizon,ChameleonCloud/horizon,bac/horizon,anthonydillon/horizon,dan1/horizon-x509,Tesora/tesora-horizon,coreycb/horizon,gerrive/horizon,django-leonardo/horizon,davidcusatis/horizon,dan1/horizon-x509,redhat-cip/horizon,idjaw/horizon,Tesora/tesora-horizon,takeshineshiro/horizon,ChameleonCloud/horizon,ChameleonCloud/horizon,bac/horizon,saydulk/horizon,openstack/horizon,noironetworks/horizon,FNST-OpenStack/horizon,Dark-Hacker/horizon,Mirantis/mos-horizon,wolverineav/horizon,BiznetGIO/horizon,bigswitch/horizon,yeming233/horizon,dan1/horizon-x509,openstack/horizon,anthonydillon/horizon,Mirantis/mos-horizon