doc/ffserver: merge paragraph starting with "What happens next?" with previous one

The name of the paragraph sounded a bit silly, and its text is small so
it's better to merge it with the previous paragraph.
avcodec/takdec: move tmp declaration to where its used

Makes the code a bit easier to read

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/takdec: remove unused variable

Found-by: CSA
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>