[1.4] fixed some PHP 5.4 notices (closes #10010, patch from Tiago.Ribeiro, David.Regade, and bmontuelle)

git-svn-id: http://svn.symfony-project.com/branches/1.4@33596 ee427ae8-e902-0410-961c-c3ed070cd9f9
[1.4] fixed the possibility to fake a file upload

git-svn-id: http://svn.symfony-project.com/branches/1.4@33598 ee427ae8-e902-0410-961c-c3ed070cd9f9
[1.4] updated CHANGELOG for version 1.4.20

git-svn-id: http://svn.symfony-project.com/branches/1.4@33599 ee427ae8-e902-0410-961c-c3ed070cd9f9
[1.4] bumped version

git-svn-id: http://svn.symfony-project.com/branches/1.4@33606 ee427ae8-e902-0410-961c-c3ed070cd9f9