webdav client crashes for secure connections if he doesn't have the right root...

webdav client crashes for secure connections if he doesn't have the right root certificate for ssl verification. For the moment I print at least a useful error message to the OC log and the Apache log

3rdparty/Sabre/DAV/Client.php

@@ -249,6 +249,7 @@ class Sabre_DAV_Client {
             // Automatically follow redirects
             CURLOPT_FOLLOWLOCATION => true,
             CURLOPT_MAXREDIRS => 5,
+        	//CURLOPT_SSL_VERIFYPEER	=> false,
         );
 
         switch ($method) {

apps/files_external/lib/webdav.php

@@ -96,6 +96,8 @@ class OC_FileStorage_DAV extends OC_Filestorage_Common{
 			$responseType=$response["{DAV:}resourcetype"]->resourceType;
 			return (count($responseType)>0 and $responseType[0]=="{DAV:}collection")?'dir':'file';
 		}catch(Exception $e){
+			error_log($e->getMessage());
+			\OCP\Util::writeLog("webdav client", \OCP\Util::sanitizeHTML($e->getMessage()), \OCP\Util::ERROR);
 			return false;
 		}
 	}