Rescues SystemCallError instead of Errno

[dmccown]

Fixes #344

This fixes issue #344 by replacing rescue Errno::* with
SystemCallError. Each error in the Errno::Constants is a subclass of
SystemCallError. We can use SystemCallError to handle the exceptions on
different OSes.

Signed-off-by: David McCown dmccown@chef.io

[jquick]

Thanks @dmccown