test: Thrasher: restore changed options after done with thrash

Signed-off-by: Kefu Chai <kchai@redhat.com>

qa/tasks/ceph_manager.py

@@ -138,7 +138,13 @@ def tmp(x):
             self.config = dict()
         # prevent monitor from auto-marking things out while thrasher runs
         # try both old and new tell syntax, in case we are testing old code
-        self._set_config('mon', '*', 'mon-osd-down-out-interval', 0)
+        self.saved_options = {}
+        first_mon = teuthology.get_first_mon(manager.ctx, self.config).split('.')
+        opt_name = 'mon_osd_down_out_interval'
+        self.saved_options[opt_name] = manager.get_config(first_mon[0],
+                                                          first_mon[1],
+                                                          opt_name)
+        self._set_config('mon', '*', opt_name, 0)
         # initialize ceph_objectstore_tool property - must be done before
         # do_thrash is spawned - http://tracker.ceph.com/issues/18799
         if (self.config.get('powercycle') or
@@ -857,6 +863,9 @@ def do_thrash(self):
             if self.ceph_manager.get_pool_pg_num(pool) > 0:
                 self.fix_pgp_num(pool)
         self.pools_to_fix_pgp_num.clear()
+        for opt, value in self.saved_options.iteritems():
+            self._set_config('mon', '*', opt, value)
+        self.saved_options.clear()
         self.all_up()