pyuv >= 1.0.0 has 'getaddrinfo()' in 'dns' module

From the first stable version on, pyuv has moved the 'getaddrinfo()' function from the 'util' module to the 'dns' module. This patch reflects this change.

If wanted for, I could modify it to fall back to 'util' when an import error occurs (just to preserve backwards compatibility), though I'd rather not.