Add mintsystem to CHECK_UP_TO_DATE

Author: clefebvre

usr/bin/mintupgrade

@@ -16,7 +16,7 @@ SUPPORTED_EDITIONS = ["cinnamon"]
 
 CHECK_ABSENT = ["libservlet3.1-java"]
 CHECK_PRESENT = ["default-jre"]
-CHECK_UP_TO_DATE = ["mintupgrade", "apt", "dpkg", "linuxmint-keyring", "debian-archive-keyring"]
+CHECK_UP_TO_DATE = ["mintupgrade", "apt", "dpkg", "linuxmint-keyring", "debian-archive-keyring", "mintsystem"]
 
 BACKUP_APT_SOURCES = os.path.expanduser("~/Upgrade-Backup/APT/")
 BACKUP_FSTAB = os.path.expanduser("~/Upgrade-Backup/fstab")