Fix query running in the vm sandbox

[pofider]

The basic query hangs if it is executed through nodejs vm sandbox.
The problem is that the driver uses this code to verify if parameter is callback

if (params instanceof Function) 

This gives false for function in the vm sandbox. See this described here.
The correct way for checking if the parameter is function is this

if (typeof params === 'function') {

I submitted the fix in one place and also test. Unfortunately it hangs when it runs with mocks. I was not able to find out why.

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[pofider]

I actually signed your CLA.