I noticed that Xcode 7 creates a new .xcscmblueprint file in the xcshareddata folder. Will it be always auto generated? Should this file be added to th
I think it depends. Just like @Ewan Mellor said the reason for ignore .xcscmblueprint is same with it for .xccheckout.
But whether ignore .xccheckout depends on your project . If you are using single project there is no need. If you are using workspace committing xccheckout file is need. For more the answer @Chris Hanson published is feed your need.
Back to the question. The content of the xcscmblueprint contains the main information about your project.

And I'm not sure it will change in the future. As the same reason for xccheckout I would like to commit this file.