Switch to static content for glance upload test

glance is able to fetch an image from a given url.
Previously the dashboard main page was used as image,
this change sets it a static image, in order
the have less gate issue.

Any url could be used which does not requires authentication.

Change-Id: I66760790aa7d2d0d7b8c53d62baf59134b9b44d6
Merge "Switch to static content for glance upload test"