Session: Change getInstance to create a new session by default.
Session: Change getInstance to create a new session by default.

Most of the places which currently call getInstance without a parameter
expects a session to be returned.


git-svn-id: a243b28a2a52d65555a829a95c8c333076d39ae1@564 44740490-163a-0410-bde0-09ae8108e29a

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