#26551 With a tank project command, when path is not recognized, the project context is preferred.

If you are using a project specific tank command, the project with which you are being associated is implied by the location of the tank command. 

If you do `tank /tmp/foo/bar`, a project specific tank command resolves to the Empty Context, because the path `/tmp/foo/bar` does not match any project path. 

With this change, the tank command will fall back and default to a project context rather than an empty context in the case a context cannot be determined.