Added limit to image-list in a preparatory step toward addressing bug 1001345.

Currently novaclient doesn't use the limit or marker params.
As a step to addressing bug 1001345 which requires pagination,
this patch introduces the use of limit as an option
passed to the image-list function.

Change-Id: Ia32f9e923b4eb9bcdde3b7bc1722c59d7791d104
Merge "Added limit to image-list in a preparatory step toward addressing bug 1001345."