Travis CI: don't require Fontconfig binaries
Travis CI: don't require Fontconfig binaries

Only the library is needed.

In fact, `apt-get install fontconfig` didn't even install the library at
all. Luckily, the package we actually want is preinstalled on Travis CI.
We could continue to rely on this fact and completely remove Fontconfig
from the install list, but it's clearer and possibly more future-proof
to explicitly list it there.

MrSmile/libass,Akemi/libass,xbmc/libass,astiob/libass,Akemi/libass,astiob/libass,Akemi/libass,ShiftMediaProject/libass,xbmc/libass,MrSmile/libass,ShiftMediaProject/libass,libass/libass,libass/libass