Fixing variable name when overwriting input file.

It looks like at one time the variable referencing the input file was
'path', and later on it was changed to 'json', but the if
(options.inplace) block was never updated.

lib/cli.js

@@ -104,7 +104,7 @@ function main (args) {
     var json = path.normalize(options.file);
     source = parse(fs.readFileSync(json, "utf8"));
     if (options.inplace) {
-      fs.writeSync(fs.openSync(path,'w+'), source, 0, "utf8");
+      fs.writeSync(fs.openSync(json,'w+'), source, 0, "utf8");
     } else {
       if (! options.quiet) { console.log(source)};
     }