Additional apt-get update to fix key errors found

1. The initial failures are happening because of package installation failures
because of apt key issues - apt-get install throwing warnings "packages cannot
be authenticated". A manual apt-get update fixed that problem (I tried it in two
different acceptance test environments).

So added a fix for that - if apt-get install fail, repeat apt-get update.

2. Repeating puppet apply was not working because of a typo (missing escape on
collecting return value. Fixed it by escaping it.

updated the slack conversation in the issue #211