KAFKA-3199 LoginManager should allow using an existing Subject

[utenakr]

LoginManager or KerberosLogin (for > kafka 0.10) should allow using an existing Subject. If there's an existing subject, the Jaas configuration won't needed in getService()

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[ijuma]

cc @rajinisivaram

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[kunickiaj]

Any update on what's going on with this?

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