add vendoring with go dep

vendor/github.com/influxdata/influxdb/influxql/cast.go

@@ -0,0 +1,41 @@
+package influxql
+
+func castToFloat(v interface{}) float64 {
+	switch v := v.(type) {
+	case float64:
+		return v
+	case int64:
+		return float64(v)
+	default:
+		return float64(0)
+	}
+}
+
+func castToInteger(v interface{}) int64 {
+	switch v := v.(type) {
+	case float64:
+		return int64(v)
+	case int64:
+		return v
+	default:
+		return int64(0)
+	}
+}
+
+func castToString(v interface{}) string {
+	switch v := v.(type) {
+	case string:
+		return v
+	default:
+		return ""
+	}
+}
+
+func castToBoolean(v interface{}) bool {
+	switch v := v.(type) {
+	case bool:
+		return v
+	default:
+		return false
+	}
+}