Increase timeout for yum install of development tools

This command has proved to take more than puppet default
timeout to install, causing to be aborted and following errors
on puppet installing packages.
Increase to 1800 to give more room for command to be
completed.

Change-Id: I774ec74541797b279b380e0337a6114c80912447

manifests/slave.pp

@@ -45,6 +45,7 @@ class jenkins::slave(
       exec { 'yum Group Install':
         unless  => '/usr/bin/yum grouplist "Development tools" | /bin/grep "^Installed [Gg]roups"',
         command => '/usr/bin/yum -y groupinstall "Development tools"',
+        timeout => 1800,
       }
 
       if ($::operatingsystem != 'Fedora') {