add backticks to SQL, use limit parameter instead of LIMIT SQL

apps/calendar/lib/import.php

apps/calendar/lib/repeat.php

apps/calendar/lib/share.php

apps/calendar/lib/share/calendar.php

apps/calendar/lib/share_backend.php

apps/contacts/appinfo/migrate.php

apps/contacts/appinfo/update.php

apps/contacts/lib/share/addressbook.php

apps/contacts/lib/vcard.php

apps/files/appinfo/update.php

apps/files_sharing_log/index.php

apps/files_sharing_log/log.php

apps/gallery/appinfo/app.php

apps/gallery/appinfo/update.php

apps/gallery/lib/photo.php

apps/media/lib/share/artist.php

apps/media/lib/share/song.php

apps/user_ldap/appinfo/update.php

apps/user_ldap/lib/access.php

apps/user_ldap/lib/jobs.php