media: Only build when no variant is set

Change-Id: I4363e0c9163050932a52711d080b0957e1d5925c
Only build when no media variant is set, and display variant isn't legacy

* Fixes change I4363e0c9163050932a52711d080b0957e1d5925c

Change-Id: Id7e5f5f5019fec5cce169d7ff5fe7d3c707562eb
Merge pull request #6 from CyanogenMod/cm-10.1

Cm 10.1