nfs4: Fix kmemleak when allocate slot failed
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v4.9.333 by commit 84b5cb476903003ae9ca88f32b57ff0eaefa6d4c, it was introduced in version v3.12 by commit abf79bb341bf52f75f295b850abdf5f78f584311. For more details please see the references link.