dist/common/scripts/node_exporter_install: use curl instead of wget
dist/common/scripts/node_exporter_install: use curl instead of wget

CentOS/Ubuntu contains curl on minimal instllation but wget doesn't,
and we already has dependency for curl, so we should switch to curl.

Fixes #1902

Signed-off-by: Takuya ASADA <4ebfb6f510af412d6e89fefa3ab96d9c8b5e3fff@scylladb.com>
Message-Id: <1480929047-2347-1-git-send-email-4ebfb6f510af412d6e89fefa3ab96d9c8b5e3fff@scylladb.com>

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