fix warning in ProStringList_join
fix warning in ProStringList_join

Fix C4267 MSVC warning.
Make sepSize an int, because this function is never called with a size_t.

Change-Id: I2b834fe7c1408e34d55d9f137231e2f5816f3f1d
Reviewed-by: Oswald Buddenhagen <6a8868beda3e139b5ac22b2534a23d3e6ba81819@digia.com>
(cherry picked from qtbase/98a73e16012f75934ce4b6e4c85fb4d6a2ad0a28)
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@digia.com>
Reviewed-by: hjk <f81b91af79013637d070c18d38a75b90eaae8ba3@nokiamail.com>

mer-qt/qttools,mer-qt/qttools,mer-qt/qttools,mer-qt/qttools,mer-qt/qttools,mer-qt/qttools