mds: disable `defer_client_eviction_on_laggy_osds' by default

This config can result in a single client holding up mds to service
other clients since once a client is deferred from eviction due to
laggy OSD(s), a new clients cap acquire request can be possibly
blocked until the other laggy client resumes operation, i.e., when
the laggy OSD is considered non-laggy anymore.

Disable the config by default till the issue is fixed.

Fixes: http://tracker.ceph.com/issues/64685
Signed-off-by: Venky Shankar <[email protected]>

Author: vshankar

src/common/options/mds.yaml.in

@@ -1582,7 +1582,7 @@ options:
   long_desc: Laggy OSD(s) can make clients laggy or unresponsive, this can
     lead to their eviction, this option once enabled can help defer client
     eviction.
-  default: true
+  default: false
   services:
   - mds
   flags: