fix for cases in which no nal is found in entire buffer
fix for cases in which no nal is found in entire buffer

git-svn-id: 7cbbca2412464347adb5e4bdc42efeec62dad2f5@11 bc2f0a9b-661e-0410-ac89-ff65b7b8b7c4

krieger-od/h264bitstream,krieger-od/h264bitstream,sjtu-mc/h264bitstream,sjtu-mc/h264bitstream,aizvorski/h264bitstream,aizvorski/h264bitstream,aizvorski/h264bitstream,sjtu-mc/h264bitstream