Since --page-size has never worked, there is no paginate logic needs
to be implemented in "image list" command. So remove the unnecessary
loop.
And also, the marker is not necessary because --marker option has not
been implemented. Will add it back when implementing --marker option.
Change-Id: I71fea1502f92f447a49697edb52e8e82f336772f
Partial-Bug: #1540988