[TASK] Coding style: Fix usage of 'finally' reserved word

Because finally is a reserved word in JavaScript and reserved keywords are not supported as property names by ES3, we need to invoke the method like promise['finally'](callback) to make the code IE8 and Android 2.x compatible.
Merge pull request #1786 from vhpoet/develop

[TASK] Coding style: Fix usage of 'finally' reserved word