CLONE -Trim spaces from changeset ids entered in 'scroll to changeset' box

Questions raised in the original review needed addressing but weren't related to the code in the review as such.

Here's what I am to do:
1) Moved from non standard defaultValue attribute to jQuery data holder,
2) Rationalise code to one copy across the sites,
3) Remove redundant code, and
4) Only call the method when its required