Do not display debug messages during scans

[pombredanne]

Using the latest beta3, I see this during a package scan:

  create_package_and_deps: handler: <class 'packagedcode.win_pe.WindowsExecutableHandler'>
  create_package_and_deps: handler: <class 'packagedcode.win_pe.WindowsExecutableHandler'>
  create_package_and_deps: handler: <class 'packagedcode.win_pe.WindowsExecutableHandler'>
  create_package_and_deps: handler: <class 'packagedcode.pypi.PythonInstalledWheelMetadataFile'>

[AyanSinhaMahapatra]

This has landed in develop. Closing.