grub2: insecure permissions in bootloader configuration

From the Red Hat bugzilla entry:

A security flaw was found in the way bootloader configuration module of Anaconda, a graphical system installer, stored password hashes when performing write of password configuration file (0755 permissions were used instead of 0700 ones). A local users could use this flaw to obtain password hashes and conduct brute force password guessing attacks (possibly leading to password circumvention, machine reboot or use of custom kernel or initrd command line parameters).