Check sudoers file after editing

"visudo -c" should be run after the sudoers file has been edited. This
will ensure that the file is still syntactically correct, and exit 1 if
it isn't.  Otherwise, obscure errors can occur later on, and it is
difficult to track them back to this script as the source of the error.

Change-Id: Id0e5114d72c0779952a0c2c2c06696929c6c8b17

elements/rpm-distro/pre-install.d/00-usr-local-bin-secure-path

@@ -7,3 +7,4 @@ set -eu
 set -o pipefail
 
 sed -i '/secure_path/ s/$/:\/usr\/local\/bin/' /etc/sudoers
+visudo -c