Merged r13184 from trunk to 2.5-stable (#13932)

Fix file upload does not work with Safari.

Contributed by Felix Schäfer.

git-svn-id: http://svn.redmine.org/redmine/branches/2.5-stable@13187 e93f8b46-1217-0410-a6f0-8f06a7374b81
Merged r13185 from trunk to 2.5-stable (#17301)

Czech translation updated by Karel Pičman.

git-svn-id: http://svn.redmine.org/redmine/branches/2.5-stable@13188 e93f8b46-1217-0410-a6f0-8f06a7374b81