Do not use those commands when they are not exist.
Do not use those commands when they are not exist.

Sometimes we may get these errors:
scripts/scripts-library.sh: line 199: lxc-ls: command not found
scripts/scripts-library.sh: line 201: lxc-checkconfig: command not found
scripts/scripts-library.sh: line 209: ansible: command not found
There is no need to use them since they may not be installed yet.

Change-Id: I5e78bf39df0b8b7095cd6f9e0ce14a3adc39df66

openstack/openstack-ansible,cfarquhar/openstack-ansible,stackforge/os-ansible-deployment,bunchc/openstack-ansible,robb-romans/openstack-ansible,stackforge/os-ansible-deployment,yanyao/openstack-ansible,openstack/openstack-ansible,cloudnull/os-ansible-deployment,bunchc/openstack-ansible,robb-romans/openstack-ansible,cloudnull/os-ansible-deployment,cfarquhar/openstack-ansible,yanyao/openstack-ansible