libavcodec minor version is > 99 so fix the formating

libavcodec minor version is > 99 so when printing the library versions
the output is a little bit broken:

  libavutil    50. 36. 0 / 50.36. 0
  libavcore     0. 16. 1 /  0.16. 1
  libavcodec   52.108. 0 / 52.108. 0
  libavformat  52. 94. 0 / 52.94. 0
  libavdevice  52.  2. 3 / 52. 2. 3
  libavfilter   1. 74. 0 /  1.74. 0
  libswscale    0. 12. 0 /  0.12. 0

Change the formating to look like this:

  libavutil    50. 36. 0 / 50. 36. 0
  libavcore     0. 16. 1 /  0. 16. 1
  libavcodec   52.108. 0 / 52.108. 0
  libavformat  52. 94. 0 / 52. 94. 0
  libavdevice  52.  2. 3 / 52.  2. 3
  libavfilter   1. 74. 0 /  1. 74. 0
  libswscale    0. 12. 0 /  0. 12. 0

Signed-off-by: Mans Rullgard <mans@mansr.com>