Fix Android icon.

Load / save the image using Gimp, removing the
embedded sRGB profile.
Fix libpng warning: "Duplicate iCCP chunk when loading"
which shows on opening the preferences dialog.

Change-Id: I5d77eb4bb723f579dad14b3fd1985cedd2bb97a4
Reviewed-by: BogDan Vatra <bog_dan_ro@yahoo.com>
Reviewed-by: Tobias Hunger <tobias.hunger@nokia.com>