git_jira_fix_version_check.py should identify fixed Jira without any commit

Now that we have script git_jira_fix_version_check to identify all commits that have no corresponding Jira with expected fixVersion available, we should also let it figure out the diff the other way around i.e identify all Jiras that are marked resolved with given fixVersion but have no commit present with Jira number included.

RC preparation also needs to find this diff because we don't want to provide extra Jira in CHANGELOG without any corresponding commits present on git (unless it is svn checkin and fixVersion is relevant).