Detect and address condition where analyzer-extracted files might have file modes unset, preventing cleanup of analysis scratch space.  Fixes #579.
Detect and address condition where analyzer-extracted files might have file modes unset, preventing cleanup of analysis scratch space.  Fixes #579.

Signed-off-by: Daniel Nurmi <fdebf2174dd81b443340a1b87c16a0d53605a1f3@anchore.com>

anchore/anchore-engine,anchore/anchore-engine,anchore/anchore-engine