vagrant: set sudoers permissions to 0440 (#142)

Fixes CentOS bug 15552.

Author: lpancescu

vagrant/centos6.ks

@@ -75,7 +75,8 @@ mkswap /swapfile
 echo "/swapfile none swap defaults 0 0" >> /etc/fstab
 
 # sudo
-echo "%vagrant ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers.d/vagrant
+echo "%vagrant ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/vagrant
+chmod 0440 /etc/sudoers.d/vagrant
 
 # Fix for https://github.com/CentOS/sig-cloud-instance-build/issues/38
 cat > /etc/sysconfig/network-scripts/ifcfg-eth0 << EOF

vagrant/centos7.ks

@@ -84,7 +84,8 @@ mkswap /swapfile
 echo "/swapfile none swap defaults 0 0" >> /etc/fstab
 
 # sudo
-echo "%vagrant ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers.d/vagrant
+echo "%vagrant ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/vagrant
+chmod 0440 /etc/sudoers.d/vagrant
 
 # Fix for https://github.com/CentOS/sig-cloud-instance-build/issues/38
 cat > /etc/sysconfig/network-scripts/ifcfg-eth0 << EOF