[BugFix] Using memcached on HHVM

[rms230]

This fix is specificly for HHVM, when adding servers there is an undefined index error.

[Maks3w]

I think this needs a more in depth analisys.

• There are more occurrences of addServers($servers)
• May this should be done in the return of $resource->getServerList()

[Maks3w]

@rms230 I'll close this due inactivity.

[gianarb]

@Maks3w this closure's motivation is an internal role of @zendframework/community-review-team team? :)
Because into the ZF2 repo there are a lot of "inactive pr" 👍

[weierophinney]

Re-opening. This corrects a number of issues on HHVM, bringing us closer to having the component work on that platform.

[Maks3w]

@weierophinney Seriously?

[Maks3w]

I think this needs a more in depth analisys.

There are more occurrences of addServers($servers)
May this should be done in the return of $resource->getServerList()

[weierophinney]

@Maks3w It's a start, which is far better than not taking it at all and leaving it completely uncorrected.