Race condition in ListImageFilters tests

The server may not have moved back to ACTIVE state for
a short period after the image has been successfully
uploaded - so wait for the server to be ACTIVE
before continuing with the tests

Change-Id: I2d471c83d902a408004a4b2ccb8b42fdfcd764b0
Closes-bug: 1258635
Merge "Race condition in ListImageFilters tests"