(PUP-2349) Specify mode as an octal string consistently in spec manifest snippets
In the puppet 4.0 parser, the file resource's mode property will be
required to be a string containing an octal (or symbolic) representation
of mode.
For consistency then, this commit changes all cases where mode was
specified as a Numeric to be a string containing an octal representation
of mode (always prefaced with a 0, again for clarity and consistency).