Move network test_quotas to admin directory

Replace superclass base.BaseNetworkTest with base.BaseAdminNetworkTest
Remove duplicate annocation

Change-Id: I95d3175ed2b97724c6e49ab2dbe771e3dcf7a7d7
Merge "Move network test_quotas to admin directory"
Merge commit 'refs/changes/65/81565/2' of git://gold.eng.hq.xensource.com/git/github/openstack/tempest into tmpbranch