data_resource lookup uses data_resource::name(), which uses sprint(), which
uses (indirectly) locale, which takes a global lock. This is a bottleneck
on large machines.
Fix by not using name() during lookup.
Fixes #1419
Message-Id: <1467616296-17645-1-git-send-email-avi@scylladb.com>
(cherry picked from commit 76cc0c0cf9)