add vendoring with go dep

vendor/github.com/influxdata/influxdb/pkg/limiter/fixed.go

@@ -0,0 +1,19 @@
+// Package limiter provides concurrency limiters.
+package limiter
+
+// Fixed is a simple channel-based concurrency limiter.  It uses a fixed
+// size channel to limit callers from proceeding until there is a value available
+// in the channel.  If all are in-use, the caller blocks until one is freed.
+type Fixed chan struct{}
+
+func NewFixed(limit int) Fixed {
+	return make(Fixed, limit)
+}
+
+func (t Fixed) Take() {
+	t <- struct{}{}
+}
+
+func (t Fixed) Release() {
+	<-t
+}