divideSeries function not handling missing denominators the same as Graphite web

[carrieedwards]

In the divideSeries function, if the length of the denominators is not equal to 1, an error is returned in CarbonAPI. This appears to not be consistent with how this situation is handled in Graphite web, where a list of with values of None is returned.

Currently, we are seeing the following error when the length of denominators is either 0 or > 1:

function=divideSeries: found wildcard where series expected

To reproduce, run a query such as:

divideSeries(testMetric1,test)

where test is not a valid metric name.