Change to protocol-less URI
Change to protocol-less URI

The protocol check is not needed when the only part of the URI that changes is the protocol.

Can simply use _//ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js_ as the src attribute and it will work in both HTTP and HTTPS cases.

Reference: [section 4.2 of RFC 3986](http://tools.ietf.org/html/rfc3986#section-4.2)

zipme/redmine_lightbox,paginagmbh/redmine_lightbox2,endocode/redmine_lightbox2,planio-gmbh/redmine_lightbox,paginagmbh/redmine_lightbox2,zipme/redmine_lightbox,Undev/redmine_lightbox,endocode/redmine_lightbox2,paginagmbh/redmine_lightbox2,Undev/redmine_lightbox,planio-gmbh/redmine_lightbox,endocode/redmine_lightbox2,planio-gmbh/redmine_lightbox,zipme/redmine_lightbox