API: fix a type in storage_proxy
API: fix a type in storage_proxy

This patch fixes a typo in the URL definition, causing the metric in the
jmx not to find it.

Fixes #1821

Signed-off-by: Amnon Heiman <ed5fc74c4692051ad0b19749fd7cea6ec2d74b9e@scylladb.com>
Message-Id: <1478563869-20504-1-git-send-email-ed5fc74c4692051ad0b19749fd7cea6ec2d74b9e@scylladb.com>

avikivity/scylla,duarten/scylla,raphaelsc/scylla,avikivity/scylla,scylladb/scylla,raphaelsc/scylla,raphaelsc/scylla,scylladb/scylla,duarten/scylla,scylladb/scylla,duarten/scylla,avikivity/scylla,scylladb/scylla