Remove an unused variable from tests.py
Remove an unused variable from tests.py

The varialbe 'size' in TestFile.testMetadataNumberLimit is not used.
This patch remove the variable from the test.

Change-Id: I255a1dcee12bb6b8dec6ff26ed7edf93ab2acf64

hurricanerix/swift,prashanthpai/swift,matthewoliver/swift,smerritt/swift,notmyname/swift,notmyname/swift,notmyname/swift,tipabu/swift,hurricanerix/swift,smerritt/swift,openstack/swift,psachin/swift,matthewoliver/swift,swiftstack/swift,smerritt/swift,larsbutler/swift,hurricanerix/swift,openstack/swift,prashanthpai/swift,nadeemsyed/swift,redbo/swift,clayg/swift,swiftstack/swift,nadeemsyed/swift,redbo/swift,hurricanerix/swift,tipabu/swift,openstack/swift,tipabu/swift,psachin/swift,clayg/swift,openstack/swift,matthewoliver/swift,psachin/swift,swiftstack/swift,tipabu/swift,clayg/swift,matthewoliver/swift,nadeemsyed/swift,notmyname/swift,clayg/swift,larsbutler/swift,nadeemsyed/swift,smerritt/swift,psachin/swift