Set uWSGI to listen on socket by default

If you set `web_server` to anything but `"apache"`, the
default settings broke and rose a

```
Chef::Log.error!("uwsgi cannot bind to ports less than 1024. Please set \"node[graphite][listen_port]\" to an appropriate value")
```

This setting fixes the default behavior for uWSGI without
altering the default behavior for Apache.

This should fix hw-cookbooks/graphite#139 as well.
Use Chef::Log.error

Uses `Chef::Log.error` instead of `Chef::Log.error!`

The latter throws a NoMethodError since [this](https://github.com/opscode/chef/commit/634ad58ab14d6cfa05f56991bbc758cc3b22d410) commit in Chef.
Merge pull request #146 from Springest/uwsgi-socket-error

Set uWSGI to listen on socket by default