fix up tests.aqdb.test_network
fix up tests.aqdb.test_network

use filter to ensure it has a network with .addresses()
remove unused imports
setup() modified
remove empty fixture methods

quattor/aquilon,quattor/aquilon,stdweird/aquilon,stdweird/aquilon,quattor/aquilon,guillaume-philippon/aquilon,guillaume-philippon/aquilon,guillaume-philippon/aquilon,stdweird/aquilon