NFS: Use proper naming conventions for nfs_client.impl_id field

Clean up:  When naming fields and data types, follow established
conventions to facilitate accurate grep/cscope searches.

Additionally, for consistency, move the impl_id field into the NFSv4-
specific part of the nfs_client, and free that memory in the logic
that shuts down NFSv4 nfs_clients.

Introduced by commit 7d2ed9ac "NFSv4: parse and display server
implementation ids," Fri Feb 17, 2012.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 471fc9b..39db1be 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -238,6 +238,7 @@
 
 	rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
 	kfree(clp->cl_serverscope);
+	kfree(clp->cl_implid);
 }
 
 /* idr_remove_all is not needed as all id's are removed by nfs_put_client */
@@ -306,7 +307,6 @@
 
 	put_net(clp->net);
 	kfree(clp->cl_hostname);
-	kfree(clp->impl_id);
 	kfree(clp);
 
 	dprintk("<-- nfs_free_client()\n");