Remove "-nodes" option from make-certs scripts

Remove "-nodes" option from make-certs scripts

The openssl command does not recognize options after positional
arguments, so in "openssl genrsa $KEYSIZE -nodes", the "-nodes" was
ignored as a excess positional argument prior to OpenSSL 1.1.0h, and
now causes an error.  "-nodes" is an option to the openssl req and
pkcs12 subcommands, but genrsa creates unencrypted keys by default.

[ghudson@mit.edu: edited commit message]