ceph: initialize pathlen variable in reconnect_caps_cb

ceph: initialize pathlen variable in reconnect_caps_cb

[ Upstream commit f667a8dde2a0850098e86e8a1b7e66625ad7e7ad ]

The smatch static checker warned about an uninitialized symbol usage in
this function, in the case where ceph_mdsc_build_path returns an error.

It turns out that that case is harmless, but it just looks sketchy.
Initialize the variable at declaration time, and remove the unneeded
setting of it later.

Fixes: 2cbe9c41b8c3 ("ceph: encode inodes' parent/d_name in cap reconnect message")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>