Svn commit fails when non-english characters are in commit message

Regression of QTCREATORBUG-13728. Svn commit fails with

svn: E000022: Commit failed (details follow):
svn: E000022: Error normalizing log message to internal format
svn: E000022: Non-ASCII character (code 195) detected, and unable to convert to/from UTF-8

with commit message "äää". Command line svn, Tortoise svn GUI and Androidstudio svn integration don't behave like this.