display actual import error when import has failed

pzec/commands/import.rs

@@ -23,7 +23,7 @@ pub fn import(cfg: Config, matches: &ArgMatches) -> Result<(), String> {
 				}
 			}
 			Err(Error::TooManyOrphanBlocks) => return Err("Too many orphan (unordered) blocks".into()),
-			Err(_) => return Err("Cannot append block".into()),
+			Err(error) => return Err(format!("Cannot append block: {:?}", error)),
 		}
 	}