Increase the 3PAR hostname length

The latest 3PAR firmware supports a hostname of 31 characters.
This patch increases the hostname on the 3PAR from 23 characters to
31.

The driver currently has a fallback mechanism in place for detecting
existing hosts.   This handles the case where upgrading from
Icehouse to Juno where Icehouse hosts have a limit of 23 characters.

Change-Id: I171e54b2e03a4ae11d2bf07c9c48febab268ce84
Closes-Bug: 1371242
Merge "Increase the 3PAR hostname length"