ciao-image: Return an empty list when there are no images
ciao-image: Return an empty list when there are no images

GET /v2/images should always return a list according to OpenStack
image api V2

This change creates an empty list of image.DefaultResponse from the
begining of ListImages() rather than when the first append
to the list is done.

Fixes #892

Signed-off-by: Alberto Murillo Silva <3e496b67a60a13551c6a151e0a6a52025fbd95e6@intel.com>

mcastelino/ciao,mrkz/ciao,matthewrsj/ciao,ciao-project/ciao,mcastelino/ciao,tpepper/ciao,mrkz/ciao,obedmr/ciao,mrkz/ciao,wcwxyz/ciao,erick0z/ciao,kaccardi/ciao,01org/ciao,matthewrsj/ciao,erick0z/ciao,ciao-project/ciao,rbradford/ciao,rbradford/ciao,kaccardi/ciao,tpepper/ciao,erick0z/ciao,wcwxyz/ciao,markdryan/ciao,matthewrsj/ciao,mcastelino/ciao,markdryan/ciao,tpepper/ciao,obedmr/ciao,wcwxyz/ciao,obedmr/ciao,01org/ciao