Pass rootUri to LSPs in addition to rootPath

test/lsp/test_lsp_client_messages.vader

@@ -17,6 +17,7 @@ Execute(ale#lsp#message#Initialize() should return correct messages):
   \    'rootPath': '/foo/bar',
   \    'capabilities': {},
   \    'initializationOptions': {'foo': 'bar'},
+  \    'rootUri': 'file:///foo/bar',
   \   }
   \ ],
   \ ale#lsp#message#Initialize('/foo/bar', {'foo': 'bar'})