Fixes #5984: Build error on RPM due to man pages being included twice

We do not need to include any files from %{rudderdir} in the %files
section of the .spec file, because they are included automatically (see
the comment just before the start of the %files section)
Merge pull request #564 from jooooooon/bug_5984/build_error_on_rpm_due_to_man_pages_being_included_twice

Fixes #5984: Build error on RPM due to man pages being included twice