empty opts if it doesn't exist to prevent crashing

[ghost]

If there isn't a package.json, jadeify crashes because opts is null:

$ browserify -t jadeify rawr.js

/tmp/node_modules/jadeify/lib/jadeify.js:27
                opts.filename = fileName;
                              ^
TypeError: Cannot set property 'filename' of null
    at /tmp/node_modules/jadeify/lib/jadeify.js:27:31
    at /tmp/node_modules/jadeify/lib/jadeify.js:62:20
    at testDir (/tmp/node_modules/jadeify/node_modules/find-parent-dir/index.js:20:36)
    at /tmp/node_modules/jadeify/node_modules/find-parent-dir/index.js:26:7
    at Object.cb [as oncomplete] (fs.js:168:19)

This patch keeps jadeify from crashing.

[domenic]

Something weird must be going on. How is that stack trace even possible? Line 62 does cb(err) but line 22 does will cause an early return if err is present, so line 27 should never be hit.

Setting up a test project to find dig further...

[domenic]

Oh I misreadline 62. I see. I think the correct fix is cb(null, {}) on line 62 to be consistent with line 79.

[domenic]

Released as 2.5.1