Hi,

Whilst working on the Reproducible Builds effort [0], we noticed that
golang-github-yudai-gojsondiff could not be built reproducibly.

This is because the call to "cp -a FIXTURES […]" is not matched by a
corresponding "rm -rf […]/FIXTURES", and the results of the cp call
end up in the binary package. This means that the package differs
depending on whether the testsuite is run or not.

Patch attached that adds this rm.

 [0] https://reproducible-builds.org/


Regards,