added the ability to retrive the value of mount_ip from /etc/swift/fs.conf to gluster-swift-gen-builders

this version of gluster-swift-gen-builders can get the value of mount_ip from /etc/swift/fs.conf then it detects if its a host name or IP if its a host name it resolves it because swift-ring-builder add fails if you use a host name.
The python socket.gethostbyname method is being used to resolve because even if the hostname is only in the /etc/hosts file, where by comparison the "host" command can only resolve names in a DNS and ignores the /etc/hosts file.