Upgrade to omnibus-ctl 0.6.0

Closes #3266 (closed)

Changelog

• Enable symlinks to be found
• Explicitly calls help and exits 0 when omnibus-ctl is run with --help as the first argument
• Strips out -- to use existing help command code path
• Add license to gemspec
• Add global pre-hook support
• Fix typo preventing omnibus-ctl int <program> from working
• Remove SVDIR from environment if it was set
• Explicitly set SVDIR to the service_dir
• Quote glob patterns in find command
• Set log_level with -l

https://github.com/chef/omnibus-ctl/compare/v0.5.0...1b96ac486636cac987e5b464810bb3ff673a93fe