Fix multi collator setup (#133)

* Start

* Fix compilation

* Fix chainspec

* Don't set best 2 times for the same block

* Check the status of a block before building on it

* Check that the block exists before setting it as the new best

* Reorder code

* Fork choice depends on sync status

* Switch branch again

cumulus/network/src/lib.rs

@@ -202,7 +202,7 @@ where
 			)) as Box<_>);
 		}
 
-		Ok(Validation::Success { is_new_best: false })
+		Ok(Validation::Success { is_new_best: true })
 	}
 }