[#14507] remove NestedSet patch from config/initializers/10-patches.rb

https://www.openproject.org/work_packages/14507

There is no answer on #1863.
Comment of #2027 is non sense.

For Rails4 porting.
https://github.com/opf/openproject/commit/2e8057223cccb7743d8f018ccd37403c645751f1
http://www.redmine.org/projects/redmine/repository/revisions/13147