Fixed trailing slash bug in nla-deploy.sh

If wayback.urlprefix=/path/to/wayback/ in wayback.xml then
wayback.url=/path/to/wayback (note lack of trailing slash) in
agwa.properties.

This is because wayback.urlprefix has to have a trailing slash
but agwa.url and wayback.url in agwa.properties are specified
without trailing slashes. I wanted the URL format to be consistent
within agwa.properties at least.