ZP-1356 Revert "ZP-836 Log output without impersonated user."

This reverts commit 6434b66b.

Released under the Affero GNU General Public License (AGPL) version 3.

src/backend/kopano/kopano.php

@@ -148,7 +148,7 @@ class BackendKopano implements IBackend, ISearchProvider {
 
         // check if we are impersonating someone
         // $defaultUser will be used for $this->defaultStore
-        if ($this->impersonateUser) {
+        if ($this->impersonateUser !== false) {
             ZLog::Write(LOGLEVEL_DEBUG, sprintf("KopanoBackend->Logon(): Impersonation active - authenticating: '%s' - impersonating '%s'", $this->mainUser, $this->impersonateUser));
             $defaultUser = $this->impersonateUser;
         }