Execute radosbench test using sudo

When running a radosbench test, execute the /usr/bin/rados command with sudo
in order to ensure the client can read the admin keyring.

Closes ceph#105

benchmark/radosbench.py

@@ -134,7 +134,7 @@ def _run(self, mode, run_dir, out_dir):
             if self.pool_per_proc: # support previous behavior of 1 storage pool per rados process
                 pool_name = 'rados-bench-`hostname -s`-%s'%i
                 run_name = ''
-            rados_bench_cmd = '%s -c %s -p %s bench %s %s %s %s %s %s %s --no-cleanup 2> %s > %s' % \
+            rados_bench_cmd = 'sudo %s -c %s -p %s bench %s %s %s %s %s %s %s --no-cleanup 2> %s > %s' % \
                  (self.cmd_path_full, self.tmp_conf, pool_name, op_size_str, self.time, mode, concurrent_ops_str, max_objects_str, write_omap_str, run_name, objecter_log, out_file)
             p = common.pdsh(settings.getnodes('clients'), rados_bench_cmd)
             ps.append(p)