Install yappi package

If yappi is installed, we can get nodepool to dump thread info.

Change-Id: I88e79da77fb03c6d522f48baa19d55fd69968528

manifests/init.pp

@@ -120,11 +120,19 @@ class nodepool (
 
   if ($python_version == 3) {
     include ::pip::python3
+    $pip_provider = pip3
     $pip_command = 'pip3'
   } else {
+    $pip_provider = openstack_pip
     $pip_command = 'pip'
   }
 
+  package { 'yappi':
+    ensure   => present,
+    provider => $pip_provider,
+    require  => Class['pip'],
+  }
+
   exec { 'install_nodepool' :
     command     => "${pip_command} install -U /opt/nodepool",
     path        => '/usr/local/bin:/usr/bin:/bin/',
@@ -138,6 +146,7 @@ class nodepool (
       Package['libxml2-dev'],
       Package['libxslt1-dev'],
       Package['libgmp-dev'],
+      Package['yappi'],
     ],
     timeout     => 1000,
   }