support quotes and spaces in file names

Per http://lists.omniti.com/pipermail/omnios-discuss/2014-March/002405.html

The fixed behavior:

    % mkdir foo; touch 'foo/bar baz' 'foo/bar=baz' 'foo/bar"baz' "foo/bar'baz"; PYTHONPATH=proto/root_i386/usr/lib/python2.6/vendor-packages/ proto/root_i386/usr/bin/pkgsend generate foo
    file group=bin hash='bar"baz' mode=0644 owner=root path='bar"baz'
    file group=bin hash="bar baz" mode=0644 owner=root path="bar baz"
    file group=bin hash="bar'baz" mode=0644 owner=root path="bar'baz"
    file group=bin hash=bar=baz mode=0644 owner=root path=bar=baz

pkgsend publish works fine with these. Interestingly Oracle's docs don't
mention single quotes but publish didn't like those either so I included it
here.