* guix/scripts/system/reconfigure.scm (switch-system-program): Set
‘GUIX_NEW_SYSTEM’ to GENERATION rather than OS, for consistency with
what ‘boot-system’ does.
* gnu/tests/reconfigure.scm (run-switch-to-system-test)
["script activated the new generation"]: Adjust accordingly.
Change-Id: I57b693606a41b8c952df32bbdc2b9120c6dbfd6a