misc: fix error formatting in multiple files

pilot.go

@@ -39,7 +39,7 @@ func validateAtplCfg(cfg *autoPilotConfig) ([]*autopilot.WeightedHeuristic,
 		a, ok := autopilot.AvailableHeuristics[name]
 		if !ok {
 			// No heuristic matching this config option was found.
-			return nil, fmt.Errorf("Heuristic %v not available. %v",
+			return nil, fmt.Errorf("heuristic %v not available. %v",
 				name, availStr)
 		}
 
@@ -58,11 +58,11 @@ func validateAtplCfg(cfg *autoPilotConfig) ([]*autopilot.WeightedHeuristic,
 
 	// Check found heuristics. We must have at least one to operate.
 	if len(heuristics) == 0 {
-		return nil, fmt.Errorf("No active heuristics. %v", availStr)
+		return nil, fmt.Errorf("no active heuristics: %v", availStr)
 	}
 
 	if sum != 1.0 {
-		return nil, fmt.Errorf("Heuristic weights must sum to 1.0")
+		return nil, fmt.Errorf("heuristic weights must sum to 1.0")
 	}
 	return heuristics, nil
 }