Fix repo URL (the repo is case sensitive; it appears)

Can't install using bower.

```
$ bower install angularjs-facebook
bower not-cached    git://github.com/Ciul/Angularjs-Facebook.git#*
bower resolve       git://github.com/Ciul/Angularjs-Facebook.git#*
bower ECMDERR       Failed to execute "git ls-remote --tags --heads git://github.com/Ciul/Angularjs-Facebook.git", exit code of #128

Additional error details:
fatal: remote error:
  Repository not found.
```