Install Passenger/Nginx from packages instead of building by hand.

Upgrading an existing server should be straightforward. Just bootstrap and deploy. Existing Nginx config files will be maintained. You can optionally delete the passenger gem "gem uninstall passenger" afterwards.
Convert tabs to spaces in nginx.conf.

Tabs/spaces were used inconsistently. Spaces seems to be the standard in other config files.
Remove unneeded deploy.task blocks from deploy-passenger_nginx.rb

I believe these were copied from deploy-passenger.rb. I can't see any purpose for them in deploy-passenger_nginx.rb. I've tested creating a server, deploying, restarting Nginx, etc. and everything works without them.
Use update-alternatives to specify which version of Ruby to use.

This configures /usr/bin/ruby to run the version of Ruby installed by ruby-build.

This fixes a problem running passenger-status and passenger-memory-stats. Those commands appear to be hard-coded to use /usr/bin/ruby instead of using the Ruby in the path.
Update passenger_nginx:setup_apt_sources to use sudo_script
Preserve the system path in the Passenger/Nginx processes.

The version of Nginx installed from the Passenger packages no longer preserves system path. System path is needed in some cases. For example ImageMagick uses the system path to find delegates (like Ghostscript).
Remove duplicate nginx_log_dir.
Remove munin passenger plugins.

The format of passenger-status and passenger-memory stats changed with Passenger 4.x. These plugins no longer work. I've never found these plugins to be that helpful because:

- We lock down the number of worker processes so it never changes. No sense in graphing it.
- The biggest memory load in the system by far is the passenger workers. It's just as easy to monitor system memory as a whole vs monitoring the passenger memory. What would be really useful is monitoring memory by worker, which this plugin doesn't do.
Merge pull request #438 from willkoehler/use_passenger_nginx_packages

Install Passenger/Nginx from packages instead of building by hand