mon: ceph fails to compile with boost 1.58

src/mon/OSDMonitor.cc

@@ -2998,8 +2998,6 @@ bool OSDMonitor::preprocess_command(MMonCommand *m)
   } else if (prefix == "osd crush get-tunable") {
     string tunable;
     cmd_getval(g_ceph_context, cmdmap, "tunable", tunable);
-    int value;
-    cmd_getval(g_ceph_context, cmdmap, "value", value);
     ostringstream rss;
     if (f)
       f->open_object_section("tunable");