Only use the first 4 characters of the year if a datetime is found.

refactor_music_library.sh

@@ -163,6 +163,7 @@ function migrate_music {
 	while [[ "$year" == *"  "* ]]; do
 		year="${year//  / }"
 	done
+	year="${year:0:4}"
 	echo "*** Year=$year ($year_source)"
 
 	parent=""