BUILD: Travis advice to add dpl_version

Recently MacOS builds didn't worked anymore. Travis support suggested to
add this line:

   dpl_version: 1.10.16

into .travis.yml at the deploy section. Since it's OSX related problem,
I've added only there.

.travis.yml

@@ -186,6 +186,7 @@ matrix:
         - build/dmg-osx-creator.sh
         - build/deploy/before-deploy.sh xemu-deploy MacOS
       deploy:
+        dpl_version: 1.10.16
         provider: pages
         local_dir: xemu-deploy
         skip_cleanup: true