class_spec: fix quoting in Debian pkg_cmd

Author: kenyon

spec/acceptance/class_spec.rb

@@ -6,9 +6,10 @@
     pkg_cmd = 'yum info nodejs | grep "^From repo"'
     install_module_from_forge('puppet-epel', '>= 3.0.0 < 4.0.0')
   when 'Debian'
-    pkg_cmd = 'dpkg -s nodejs | grep ^Maintainer'
+    pkg_cmd = 'dpkg -s nodejs | grep "^Maintainer"'
     install_module_from_forge('puppetlabs-apt', '>= 4.4.0 < 8.0.0')
   end
+
   context 'default parameters' do
     let(:pp) { "class { 'nodejs': }" }