SUNRPC: rpc_call_null_helper() should set RPC_TASK_SOFT

Clean up.

All of rpc_call_null_helper() call sites assert RPC_TASK_SOFT, so
move that setting into rpc_call_null_helper() itself.

Signed-off-by: Chuck Lever <[email protected]>
Signed-off-by: Anna Schumaker <[email protected]>
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 429f174..4ecc2a9 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -1288,7 +1288,7 @@ gss_send_destroy_context(struct rpc_cred *cred)
 
 		trace_rpcgss_ctx_destroy(gss_cred);
 		task = rpc_call_null(gss_auth->client, &new->gc_base,
-				RPC_TASK_ASYNC|RPC_TASK_SOFT);
+				     RPC_TASK_ASYNC);
 		if (!IS_ERR(task))
 			rpc_put_task(task);