Fix is_service_enabled when using multiple arguments
Fix is_service_enabled when using multiple arguments

is_service_enabled might actually fail to return the expected result if
there is a is_${service}_enabled function available and multiple
services are checked.

For example, if one defines swift as a service but disables glance, the
following check fails:

 if is_service_enabled swift glance horizon; then
     install_swiftclient
 fi

This is because the second for-iteration resets the local "enabled" var
again to 1 and finally exits with 1 as a return code.

This patch fixes this.

Change-Id: Ic76b72897efe9597d1412470353895001a1a4c66

openstack-dev/devstack,thomasem/devstack,mssumanth/devstack,samgoon/devstack,olivierlemasle/devstack,pombredanne/devstack,pombredanne/devstack,richliu/devstack,group-policy/devstack,ozamiatin/devstack,Mahito/devstack,parul24/devstack,mssumanth/devstack,dtroyer/devstack,costingalan/devstack,nawawi/openstack,dtroyer/devstack,richliu/devstack,varunarya10/devstack,mc2014/devstack,bswartz/devstack,noironetworks/devstack,nawawi/openstack,avvocatodemarchis/devstack,parul24/devstack,mc2014/devstack,prithivm/branch01,TwinkleChawla/devstack,ozamiatin/devstack,bigswitch/devstack,costingalan/devstack,dirkmueller/devstack,avvocatodemarchis/devstack,varunarya10/devstack,Mahito/devstack,olivierlemasle/devstack,prithivm/branch01,vsham20/devstack,bigswitch/devstack,dirkmueller/devstack,openstack-dev/devstack,TwinkleChawla/devstack,thomasem/devstack,noironetworks/devstack,group-policy/devstack,samgoon/devstack,bswartz/devstack,vsham20/devstack