Great patch, thank you. I applied it to automysqlbackup-v3.0_rc6.
I had to set the password for "--login-path=client" instead of local, as mentioned in automysqlbackup.conf's example, to get it working.
Without this patch one would see annoying messages like "mysql: [Warning] Using a password on the command line interface can be insecure. or mysqldump: [Warning] Using a password on the command line interface can be insecure.