Fix Makefile for js68 rpm builds

[matthew-graves]

Overview

Noticed on an el8 machine that the Makefile was not copying folders over properly from js68/rpm/ and instead putting an rpm folder in rpmbuild, where there should have been SOURCES and SPECS. This led to the steps afterwards failing.

This PR fixes that issue, as well as a typo in the readme

Testing recommendations

Attempt to build the rpms for js68 via the makefile make couch-js-68-rpms

Checklist

• [x] Code is written and works correctly;
• [N/A] Changes are covered by tests;
• [N/A] Documentation reflects the changes;