Don't require relative entrypoint file path to begin with ./

[ZimbiX]

When specifying the entrypoint file path without a ./, it doesn't work:

➜ bundle exec que config/jobs_environment.rb  
Could not load file 'config/jobs_environment.rb'

vs:

➜ bundle exec que ./config/jobs_environment.rb
Que waiting for jobs...

This is confusing, and it took us digging through the source code to figure out that ./ was required, since it's passing the unmodified path through to ruby's native require method:

que/bin/command_line_interface.rb

Line 185 in 065981f

require file

We have filed a related issue for revealing the true error when loading this file: #280