Don't use slow hashing to check the LDAP binding

using password_hash is expensive and should be used for hashing
passwords when saving them in the database. Here we just want to see if
the bind was already done with the given password.

Signed-off-by: Carl Schwan <carl@carlschwan.eu>

Author: CarlSchwan

apps/user_ldap/lib/Connection.php

@@ -673,10 +673,7 @@ public function bind() {
 		if (
 			count($this->bindResult) !== 0
 			&& $this->bindResult['dn'] === $this->configuration->ldapAgentName
-			&& \OC::$server->getHasher()->verify(
-				$this->configPrefix . $this->configuration->ldapAgentPassword,
-				$this->bindResult['hash']
-			)
+			&& md5($this->configPrefix . $this->configuration->ldapAgentPassword) === $this->bindResult['hash']
 		) {
 			// don't attempt to bind again with the same data as before
 			// bind might have been invoked via getConnectionResource(),
@@ -690,7 +687,7 @@ public function bind() {
 
 		$this->bindResult = [
 			'dn' => $this->configuration->ldapAgentName,
-			'hash' => \OC::$server->getHasher()->hash($this->configPrefix . $this->configuration->ldapAgentPassword),
+			'hash' => md5($this->configPrefix . $this->configuration->ldapAgentPassword),
 			'result' => $ldapLogin,
 		];