Be consistent about host names in RouteSelector.

Use the host specified by the address, and not URI.getHost().

bug: 18023709
Change-Id: I2c39c2ce89049130dc00047c8de6f214159144c0

Originally https://android-review.googlesource.com/#/c/112027/
Closes https://github.com/square/okhttp/issues/1110