Move to ldap.v3 to fix #5928 (#6105)

Signed-off-by: Andrew Thornton <art27@cantab.net>

vendor/gopkg.in/ldap.v3/debug.go

@@ -0,0 +1,24 @@
+package ldap
+
+import (
+	"log"
+
+	"gopkg.in/asn1-ber.v1"
+)
+
+// debugging type
+//     - has a Printf method to write the debug output
+type debugging bool
+
+// write debug output
+func (debug debugging) Printf(format string, args ...interface{}) {
+	if debug {
+		log.Printf(format, args...)
+	}
+}
+
+func (debug debugging) PrintPacket(packet *ber.Packet) {
+	if debug {
+		ber.PrintPacket(packet)
+	}
+}