[SRU] Update to bug-fix release 2.2.8 in Xenial

[Impact]

VLC has received many bug fixes on the stable 2.2.x branch since 2.2.2 was released. I think 16.04 LTS should get these fixes.

[Test Case]

Install vlc from xenial-proposed and test it for at least one week. Play different video formats to catch any regressions, and use it as you normally would.

[Regression Potential]

The 2.2.x branch receives only bug fixes, which are cherry-picked from the master branch where the main development takes place. So, I think the regression potential is low.

[Other Info]

VLC 2.2 maintenance branch.
http://git.videolan.org/?p=vlc/vlc-2.2.git;a=summary

Changes between 2.2.7 and 2.2.8:
--------------------------------

Demuxers:
 * Fix AVI invalid pointer dereferences

Translations updates

Changes between 2.2.6 and 2.2.7:
--------------------------------

Decoders:
 * Fix flac heap write overflow on format change
 * Fix crash in libavcodec module (heap write out-of band) (CVE-2017-10699)
 * Fix infinite loop in sami subtitle
 * Fix AAC 7.1 channels detection

Demuxers:
 * Fix potential crash in ASX parser
 * Fix AVI read/write overflow

Mac OS X:
 * Fix compatibility with macOS High Sierra
 * Fix regression in ASS subtitle decoding
 * Fix crash during automatic update. Some users might need to manually
   update to the newest version.

Video Output:
 * Fix Direct3D9 output with odd offsets

Misc:
 * Fix crash in MTP
 * Support libupnp 1.8

Translations updates

Changes between 2.2.5.1 and 2.2.6:
----------------------------------

Video output:
 * Fix systematic green line on nvidia
 * Fix direct3d SPU texture offsets handling

Demuxer:
 * Fix heap buffer overflows

Changes between 2.2.5 and 2.2.5.1:
----------------------------------

Security hardening for DLL hijacking environments

Translations updates

Misc:
 * Update for Soundcloud, liveleak and Youtube scripts
 * Fix potential out-of-band dereference in flac decoder
 * Fix potential out-of-band reads in mpeg packetizers
 * Fix infinite loop in subtitles demuxer
 * Fix incorrect memory free in ogg demuxer
 * Fix potential out-of-band reads in subtitle decoders and demuxers
 * Fix green line on Windows with odd sizes

Changes between 2.2.4 and 2.2.5:
--------------------------------

Decoder:
 * Fix mp3 playback quality regression in libmad
 * Fix video scaling in VDPAU
 * Fix playback of palettized codecs
 * Fix ADPCM heap corruption (FG-VD-16-067)

Demuxer:
 * Fix possible ASF integer overflow
 * Fix MP4 divide-by-zero

Video output:
 * Fix green line on Windows with AMD drivers

Access:
 * Fix crash in screen recording on Windows
 * Fix FTP scan string injection

Mux:
 * Fix mp4 drift

Windows:
 * The plugins loading will not load external DLLs by default.
   Plugins will need to LoadLibrary explicitely.
 * Fix uninstaller path handling

MacOS:
 * Fix scrolling sensitivity on Sierra
 * Resume points are deleted now if the user clears the list of
   recent items

Changes between 2.2.3 and 2.2.4:
--------------------------------

Decoder:
 * Fix crash in G.711 wav files
 * Fix mp3 crash in libmad
 * Fix out-of-bound write in adpcm QT IMA codec (CVE-2016-5108)

Qt:
 * Fix resizing issues

Win32:
 * Fix overlay creation on Windows XP for DirectDraw video output

Misc:
 * Build fixes for Hurd

Translations:
 * Update of Bulgarian, Catalan, German, French, Italian, Marathi, Norwegian
   Bokmål, Norwegian Nynorsk, Portuguese, Slovak, Spanish (Mexico), Swedish,
   Simplified Chinese, and Traditional Chinese translations

Changes between 2.2.2 and 2.2.3:
--------------------------------

Demux:
 * Fix HLS quality selection and a potential stack overflow
 * Fix potential MKV infinite loop and improve MKV tags support
 * Fix WMV regression

Decoder:
 * Fix hardware decoding with libvdpau-va-gl
 * Fix crashes with libvpx
 * Use libass without caching dialog

Video Ouptut:
 * Fix green lines on Direct3D output

Skins2:
 * Fix maximizing Window in multi-screen context

Qt:
 * Fix resume where you left off
 * Fix infinite recursion in the customize dialog
 * Fix size when switching to/from the minimal interface
 * Fix size after resume toolbar is displayed

MacOS X:
 * Fix crashes in media information panel
 * Correctly respect the disable-screensaver option

Win32:
 * Allow opening more than 15 elements in Explorer

Translations:
 * Update of most translations