This fixes a few random issues that were encountered while recently

working on and testing rb-site:


When configuring file-based cache, the default cache "path" was the

  default memcached address, due to --cache-info= having that as the

  default.


Similarly, a default of memcached would trigger the wrong cache info

  default when walking users through installation. This needed to only

  be set if automating an install.


Site.settings_local_template wasn't set when constructing a Site,

  causing breakages in unit tests.


The version range check for Apache was incorrect, breaking something like

3.0.


This change fixes each of these bugs.

Tested rb-site install --advanced and choosing both memcached and

file options. Verified the defaults.
Tested the defaults when automating the install.
Tested the unit tests (with another upcoming change that fixes a recent

regression).
Tested the Apache version check with simulated versions.