Typo

doc/installation.org

 WIKI_DOMAIN_NAME=<freedns subdomain for your wiki>
 WIKI_FREEDNS_SUBDOMAIN_CODE=<freedns subdomain code for your wiki>
 MY_GPG_PUBLIC_KEY=<exported public key filename>
-MY_GPG_PRIVATE_KE=<exported private key filename>
+MY_GPG_PRIVATE_KEY=<exported private key filename>
 PUBLIC_MAILING_LIST=<name of your mailing list>
 LOCAL_NETWORK_STATIC_IP_ADDRESS=192.168.1.60
 ROUTER_IP_ADDRESS=192.168.1.254