Update server/plugins-available/shelluser_base_plugin.inc.php

Author: Till Brehm

server/plugins-available/shelluser_base_plugin.inc.php

@@ -477,7 +477,11 @@ private function _setup_ssh_rsa() {
 			// Remove duplicate keys
 			$existing_keys = @file($sshkeys, FILE_IGNORE_NEW_LINES);
 			$new_keys = explode("\n", $userkey);
-			$final_keys_arr = @array_merge($existing_keys, $new_keys);
+			if(is_array($existing_keys)) {
+				$final_keys_arr = @array_merge($existing_keys, $new_keys);
+			} else {
+				$final_keys_arr = $new_keys;
+			}
 			$new_final_keys_arr = array();
 			if(is_array($final_keys_arr) && !empty($final_keys_arr)){
 				foreach($final_keys_arr as $key => $val){