docs: Change Ohloh link to Open Hub
docs: Change Ohloh link to Open Hub

Ohloh got acquired by Synopsis and is nor Open Hub.
Change the Ohloh link in the links menu to point to Open Hub.

fzs/gitblit,fzs/gitblit,fzs/gitblit,fzs/gitblit,gitblit/gitblit,gitblit/gitblit,gitblit/gitblit,gitblit/gitblit,gitblit/gitblit,fzs/gitblit