Gallery cleanup - gallery-slidecheckbox

A gallery module with the old build files was submitted and subsequently build in a gallery build. It appears as if our build stack created a bad `build.json` file with `\r` at the name of the module name. It also built the module using the old files. The end result was a good and bad build directory. 

`gallery-slidecheckbox`
`gallery-slidecheckbox\r`

This may be the cause https://github.com/yui/yui3/issues/1331.

This pr corrects the `build.json` file and removes the suspect build files.