rpcbind regression

USN-4986-1 fixed a vulnerability in rpcbind. The update caused a regression
resulting in rpcbind crashing in certain environments. This update fixes
the problem for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM.

Original advisory details:

It was discovered that rpcbind incorrectly handled certain large data
sizes. A remote attacker could use this issue to cause rpcbind to consume
resources, leading to a denial of service.