androidenv: Don't build on Hydra

Output limit exceeded:

http://hydra.nixos.org/build/38236076
http://hydra.nixos.org/build/38235851

pkgs/development/mobile/androidenv/androidndk.nix

···
 
     meta = {
         platforms = stdenv.lib.platforms.linux;
+        hydraPlatforms = [];
     };
 }

pkgs/development/mobile/androidenv/androidsdk.nix

···
 
   meta = {
     platforms = stdenv.lib.platforms.unix;
+    hydraPlatforms = [];
   };
 }