Fix emaint sync call

Emaint sync needs to be called with an argument, in our case '-a' is
sufficient.  It also can request user input, so we allow it to sync
automatically as well.

Change-Id: Ida47e14f883fdd29ad375fd47992b4662911d1d1

install_puppet.sh

@@ -223,7 +223,7 @@ function setup_puppet_opensuse {
 }
 
 function setup_puppet_gentoo {
-    emaint sync
+    echo yes | emaint sync -a
     emerge -q --jobs=4 puppet-agent
     sed -i '/templatedir/d' /etc/puppetlabs/puppet/puppet.conf
 }