Fix for bug #1404526 using the template I found in gui2.library.models.py: ngettext("Series", 'Series', 1). Note that the same problem existed in the match_books dialog.
Merge branch 'master' of https://github.com/cbhaley/calibre

Fixes #1404526 ["Series" in plural in quickview](https://bugs.launchpad.net/calibre/+bug/1404526)