Bug 1059715 - VCard reader refactor to read contacts before importing th...

...em r=sergi
Please assign the variables right away and get rid of the `if` block:

```javascript
var reader = new VCardReader(textFromFile);
var match = textFromFile && textFromFile.match(/END:VCARD/g);
var cursor = reader.getAll();
var numContacts = match ? match.length : 0;
var numDupsMerged = 0;
var firstContact = null;
```