totemconfig.c: don't let a key of length > 128 clobber memory

• exec/totemconfig.c (totem_config_keyread): Reject a key with length

greater than that of our private_key buffer.

git-svn-id: http://svn.fedorahosted.org/svn/corosync/trunk@2038 fd59a12c-fef9-0310-b244-a6a79926bd2f