Test's random name gen now uses uuid4

This test used a random integer to generate the name of a file.  Although
it doesn't pose a real problem, it's probably better just to drop a UUID
in instead of a 3-digit number, to avoid collisions.

Partially implements blueprint: selenium-integration-testing

Change-Id: I95fd2c25dc4e2e5ddc47cd390b472c8ee2310e97
Closes-Bug: 1399219
Merge "Test's random name gen now uses uuid4"