style name contains Chinese character.

Encode style name in multibyte sring (ex,Chinese) properly with
RTFOutFuncs::Out_String().

Change-Id: Ibdd1010e28c711d7829643b60b32637ebce58bdb
Reviewed-on: https://gerrit.libreoffice.org/18247Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
(cherry picked from commit 85c62a36)
Reviewed-on: https://gerrit.libreoffice.org/18296