Fix disk-image-create's getopt error handling:
Fix disk-image-create's getopt error handling:

We originally checked the return code of getopt, but subsequently
a debugging echo has been inserted and now we are checking the
return code of "echo", which is very rarely going to be useful.

Change-Id: I054fecaf6576d5e9d42b07159bba7d50335bf6cc

radez/tripleo-image-elements,NaohiroTamura/diskimage-builder,openstack/diskimage-builder,zioproto/diskimage-builder,NaohiroTamura/diskimage-builder,rdo-management/diskimage-builder,qwefi/tripleo-image-elements,CSC-IT-Center-for-Science/diskimage-builder,qwefi/tripleo-image-elements,switch-ch/diskimage-builder,citrix-openstack-build/diskimage-builder,rdo-management/tripleo-image-elements,takahashinobuyuki/diskimage-builder,JioCloud/diskimage-builder,qwefi/tripleo-image-elements,zioproto/diskimage-builder,agroup/tripleo-puppet-elements,CSC-IT-Center-for-Science/diskimage-builder,qwefi/tripleo-image-elements,switch-ch/diskimage-builder,eantyshev/diskimage-builder,qwefi/tripleo-image-elements,takahashinobuyuki/diskimage-builder,citrix-openstack-build/diskimage-builder,agroup/tripleo-puppet-elements,eantyshev/diskimage-builder,rdo-management/tripleo-image-elements,radez/tripleo-image-elements,openstack/tripleo-image-elements,varunarya10/diskimage-builder,JioCloud/diskimage-builder,varunarya10/diskimage-builder,agroup/tripleo-puppet-elements,openstack/diskimage-builder,openstack/tripleo-image-elements,agroup/tripleo-puppet-elements,rdo-management/diskimage-builder