Fix other tests to include apt appropriately.

spec/system/apt_builddep_spec.rb

@@ -12,6 +12,7 @@ describe 'apt::builddep' do
   context 'apt::builddep' do
     it 'should work with no errors' do
       pp = <<-EOS
+      include '::apt'
       apt::builddep { 'glusterfs-server': }
       EOS
 

spec/system/apt_key_spec.rb

@@ -12,6 +12,7 @@ describe 'apt::key' do
   context 'apt::key' do
     it 'should work with no errors' do
       pp = <<-EOS
+      include '::apt'
       apt::key { 'puppetlabs':
         key        => '4BD6EC30',
         key_server => 'pgp.mit.edu',

spec/system/apt_source_spec.rb

@@ -12,6 +12,7 @@ describe 'apt::source' do
   context 'apt::source' do
     it 'should work with no errors' do
       pp = <<-EOS
+      include '::apt'
       apt::source { 'puppetlabs':
         location   => 'http://apt.puppetlabs.com',
         repos      => 'main',