Persist configIndex

[lukasmacko]

• modfied data structure that is stored in configIndex. Only names that are necessary to remove config items are persisted.
• containerID is used as identifier in configIndex and IPAM isntead of networkNamespace because remove request sent after restart does not contain network namespace

[coveralls]

Coverage increased (+0.02%) to 75.216% when pulling f111997 on lukasmacko:master into d7314aa on contiv:master.

[ondrej-fabry]

You could use . "github.com/onsi/gomega for more readable code, without gomega. prefixes all over the place.

gomega.Expect(err).To(gomega.BeNil()) -> Expect(err).To(BeNil()) reads like normal sentence.