mds: set the proper extra bl for the create request

mds: set the proper extra bl for the create request

Just in case a create request was totally completed but the client
didn't receive any unsafe and safe responses, and then when it's
retried in the MDS side it will be treated as a open request and
will miss setting the create ino for the reply message.

Finally for client it just sent a create request and then the MDS
just sent back a open reply, which will let the client miss setting
the CREATED flag and then the VFS will fail the create by returnning
a -EEXIST errno.

Fixes: https://tracker.ceph.com/issues/63265
Signed-off-by: Xiubo Li <xiubli@redhat.com>