removing executable bit from various files

3rdparty/Sabre.includes.php

3rdparty/Sabre/CalDAV/Backend/Abstract.php

3rdparty/Sabre/CalDAV/Backend/PDO.php

3rdparty/Sabre/CalDAV/Calendar.php

3rdparty/Sabre/CalDAV/CalendarObject.php

3rdparty/Sabre/CalDAV/CalendarQueryParser.php

3rdparty/Sabre/CalDAV/CalendarQueryValidator.php

3rdparty/Sabre/CalDAV/CalendarRootNode.php

3rdparty/Sabre/CalDAV/ICSExportPlugin.php

3rdparty/Sabre/CalDAV/ICalendar.php

3rdparty/Sabre/CalDAV/ICalendarObject.php

3rdparty/Sabre/CalDAV/Plugin.php

3rdparty/Sabre/CalDAV/Principal/Collection.php

3rdparty/Sabre/CalDAV/Principal/ProxyRead.php

3rdparty/Sabre/CalDAV/Principal/ProxyWrite.php

3rdparty/Sabre/CalDAV/Principal/User.php

...y/Sabre/CalDAV/Property/SupportedCalendarComponentSet.php

3rdparty/Sabre/CalDAV/Property/SupportedCalendarData.php

3rdparty/Sabre/CalDAV/Property/SupportedCollationSet.php

3rdparty/Sabre/CalDAV/Schedule/IMip.php