Minor: rectangle.js interpolate() - Initial values always overriden.

[martinfrances107]

I am porting this module into rust .. and so I see the linting errors from a more strict environment.

What is being picked up is a "value" is being written twice before being read.

In short we can drop the fake initialzation.

I want to keep the two version in sync ... so this is an upstream patch.

[martinfrances107]

Here is the associated pr #250

[martinfrances107]

this is not correct