Use mattermost v5 module (#1192)

vendor/github.com/mattermost/ldap/client.go

@@ -0,0 +1,30 @@
+package ldap
+
+import (
+	"crypto/tls"
+	"time"
+)
+
+// Client knows how to interact with an LDAP server
+type Client interface {
+	Start()
+	StartTLS(*tls.Config) error
+	Close()
+	SetTimeout(time.Duration)
+
+	Bind(username, password string) error
+	UnauthenticatedBind(username string) error
+	SimpleBind(*SimpleBindRequest) (*SimpleBindResult, error)
+	ExternalBind() error
+
+	Add(*AddRequest) error
+	Del(*DelRequest) error
+	Modify(*ModifyRequest) error
+	ModifyDN(*ModifyDNRequest) error
+
+	Compare(dn, attribute, value string) (bool, error)
+	PasswordModify(*PasswordModifyRequest) (*PasswordModifyResult, error)
+
+	Search(*SearchRequest) (*SearchResult, error)
+	SearchWithPaging(searchRequest *SearchRequest, pagingSize uint32) (*SearchResult, error)
+}