Fix exclusion output for wildignore entries

This removes an extra set of single quotes around wildignore entries
that caused it to behave unexpectedly.

`set wildignore=*.class`
Before: `- not -name "'*.class'"`
After: `- not -name "*.class"`
Merge pull request #9 from marczych/wildignore-shell-escape-fix

Fix exclusion output for wildignore entries