Corrections to view projects in old versions of impasse and create plans of tests with the same name on different versions.

Log:
- Re-added params "project" to functions "get_statistics_for_plan" and "get_statistics"
- Re-added params "project" where these functions are called.
- Added on query of these functions above the condition "AND project_id = project"

This small bug fix was necessary to correct two problems. They are:

- To view the statistics on the page "plans of tests" for old versions of redmine_impasse.
- Fix the error correlated with "plans of tests" with the same name, but in different projects. With this, we can copy plans of tests to different projects and keep them with the same name.