Similar to #818. Removes the warnings:

Warning: setting attribute ‘:distant-foreground’ of face ‘line-number-current-line’: nil value is invalid, use ‘unspecified’ instead.
Warning: setting attribute ‘:distant-foreground’ of face ‘line-number’: nil value is invalid, use ‘unspecified’ instead.

Partially fixes #793, Molokai was at least mentioned on this comment #793 (comment)

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