Config driver: update help text for force_config_drive
Config driver: update help text for force_config_drive

The supported values are 'always', 'True' and 'False'. Update the
help text to support this.

DocImpact

UpgradeImpact

NOTE: the 'always' option will be deprecated in Liberty.

Change-Id: Ib3de8402addb4657f4f6ede35792aab0b1498ff8
Partial-bug: #1403889

belmiromoreira/nova,Tehsmash/nova,vmturbo/nova,CloudServer/nova,sebrandon1/nova,ted-gould/nova,shail2810/nova,CCI-MOC/nova,watonyweng/nova,vmturbo/nova,thomasem/nova,tudorvio/nova,mahak/nova,belmiromoreira/nova,JioCloud/nova,phenoxim/nova,felixma/nova,double12gzh/nova,nikesh-mahalka/nova,tangfeixiong/nova,j-carpentier/nova,Francis-Liu/animated-broccoli,tangfeixiong/nova,rajalokan/nova,tudorvio/nova,openstack/nova,Juniper/nova,cernops/nova,ruslanloman/nova,jianghuaw/nova,alexandrucoman/vbox-nova-driver,hanlind/nova,adelina-t/nova,gooddata/openstack-nova,bigswitch/nova,petrutlucian94/nova,devendermishrajio/nova,dims/nova,j-carpentier/nova,JioCloud/nova,jianghuaw/nova,jeffrey4l/nova,mikalstill/nova,zaina/nova,TwinkleChawla/nova,mahak/nova,yatinkumbhare/openstack-nova,mmnelemane/nova,whitepages/nova,MountainWei/nova,CloudServer/nova,cernops/nova,barnsnake351/nova,mmnelemane/nova,klmitch/nova,rajalokan/nova,kimjaejoong/nova,bigswitch/nova,zaina/nova,JioCloud/nova_test_latest,CEG-FYP-OpenStack/scheduler,klmitch/nova,tealover/nova,scripnichenko/nova,blueboxgroup/nova,raildo/nova,MountainWei/nova,Juniper/nova,apporc/nova,jeffrey4l/nova,alaski/nova,jianghuaw/nova,Juniper/nova,fnordahl/nova,yatinkumbhare/openstack-nova,cloudbase/nova,JioCloud/nova_test_latest,rahulunair/nova,Yusuke1987/openstack_template,devendermishrajio/nova_test_latest,cernops/nova,takeshineshiro/nova,sebrandon1/nova,Stavitsky/nova,noironetworks/nova,akash1808/nova,mikalstill/nova,dims/nova,alaski/nova,devendermishrajio/nova_test_latest,bgxavier/nova,fnordahl/nova,barnsnake351/nova,whitepages/nova,varunarya10/nova_test_latest,gooddata/openstack-nova,bgxavier/nova,cyx1231st/nova,alexandrucoman/vbox-nova-driver,Francis-Liu/animated-broccoli,openstack/nova,zzicewind/nova,mahak/nova,mandeepdhami/nova,BeyondTheClouds/nova,yosshy/nova,ruslanloman/nova,rahulunair/nova,Tehsmash/nova,hanlind/nova,yosshy/nova,LoHChina/nova,shail2810/nova,klmitch/nova,scripnichenko/nova,vmturbo/nova,JianyuWang/nova,sebrandon1/nova,jianghuaw/nova,phenoxim/nova,blueboxgroup/nova,zhimin711/nova,noironetworks/nova,edulramirez/nova,apporc/nova,iuliat/nova,rahulunair/nova,BeyondTheClouds/nova,isyippee/nova,adelina-t/nova,alvarolopez/nova,hanlind/nova,akash1808/nova_test_latest,Stavitsky/nova,akash1808/nova_test_latest,ted-gould/nova,NeCTAR-RC/nova,varunarya10/nova_test_latest,edulramirez/nova,joker946/nova,CEG-FYP-OpenStack/scheduler,NeCTAR-RC/nova,tealover/nova,zhimin711/nova,raildo/nova,isyippee/nova,dawnpower/nova,mikalstill/nova,takeshineshiro/nova,mandeepdhami/nova,eonpatapon/nova,akash1808/nova,thomasem/nova,Juniper/nova,cyx1231st/nova,eonpatapon/nova,joker946/nova,nikesh-mahalka/nova,devendermishrajio/nova,cloudbase/nova,alvarolopez/nova,TwinkleChawla/nova,openstack/nova,watonyweng/nova,klmitch/nova,CCI-MOC/nova,Yusuke1987/openstack_template,cloudbase/nova,iuliat/nova,vmturbo/nova,dawnpower/nova,zzicewind/nova,LoHChina/nova,rajalokan/nova,rajalokan/nova,kimjaejoong/nova,JianyuWang/nova,BeyondTheClouds/nova,petrutlucian94/nova,double12gzh/nova,felixma/nova,gooddata/openstack-nova,gooddata/openstack-nova