nfs: fix memory leak in error path of nfs4_do_reclaim

Commit c77e2283 ("NFSv4: Fix a potential sleep while atomic in
nfs4_do_reclaim()") separate out the freeing of the state owners from
nfs4_purge_state_owners() and finish it outside the rcu lock.
However, the error path is omitted. As a result, the state owners in
"freeme" will not be released.
Fix it by adding freeing in the error path.

Fixes: c77e2283 ("NFSv4: Fix a potential sleep while atomic in nfs4_do_reclaim()")
Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
Cc: stable@vger.kernel.org # v5.3+
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>