Guard eventlog processing with its own env var

NIGHTLY was the wrong choice. Create new one EVENTLOGGING.

run-ci

@@ -67,7 +67,7 @@ ONLY_PACKAGES=( $ONLY_PACKAGES )
 export EVENTLOG_DIR="$(pwd)/run/eventlogs"
 mkdir -p $EVENTLOG_DIR
 
-if [[ -v NIGHTLY ]]; then
+if [[ -v EVENTLOGGING ]]; then
     LOGGING_GHC="$(pwd)/logging-ghc"
     LOGGING_OPTION="--logging-wrapper=$LOGGING_GHC"
 else