Edric Milaret authored Mar 21, 2016 and Guillaume Roguez committed Mar 21, 2016

CodecModel used to be in the Audio namespace, this was
changed last year, but the install guidelines were accidentally
not updated. This commit fix that.

This is related to gerrit change #3889.

Change-Id: I3a2ed126d2993d97400b06d26e6c64f39a359f67
Tuleap: #350