android: Don't add private header include directories when building the full VLC...

android: Don't add private header include directories when building the full VLC tree

These aren't necessary any longer.

The approach of adding private headers to the build of the VLC
core doesn't work well if one wants to target multiple private
ABI versions in one build.

Instead, small shared libraries for each private ABI version
can be built separately.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>