Manage graph and xdai node errors properly

[GriffGreen]

https://gov.tecommons.org/#/proposal/12

^^ This proposal is some times visible on the dapp... sometimes not...?

I might have submitted it twice cause it didnt seem to work...?

[sembrestels]

Maybe it's a problem with the graph or xdai nodes. I can't reproduce the problem but a better message error when those services are down would be appreciated.