DNS lookups failing when `ndots` is specified in /etc/resolv.conf

Parent bug: https://bugs.ruby-lang.org/issues/10412

This was fixed and backported into ruby 2.0.0, but as we are targeting 1.9.3, we'll need to patch this ourselves.

Found by @tylerjl.

Reproducing:

```
>> Resolv::DNS.new(nameserver: "8.8.8.8", search: "foo", ndots: 2).getaddress("google.com")
Resolv::ResolvError: DNS result has no information for google.com
```

Looking up a rooted (with `.` at the end) name works, though, indicating this is an ndots/search problem:

```
>> Resolv::DNS.new(nameserver: "8.8.8.8", search: "foo", ndots: 2).getaddress("google.com.")
=> #
```