(maint) Add debug messages for silently catched errors

This commit adds a debug message where errors (in the
`Puppet::Util::Windows::SID::name_to_principal` method) were caught
silently and increased dificulty in debugging said code
(`Puppet::Util::Windows::SID::Principal::lookup_account_name` in
particular).

Author: luchihoratiu

lib/puppet/util/windows/sid.rb

@@ -74,11 +74,13 @@ def name_to_principal(name, allow_unresolved = false)
         string_to_sid_ptr(name) do |sid_ptr|
           raw_sid_bytes = sid_ptr.read_array_of_uchar(get_length_sid(sid_ptr))
         end
-      rescue
+      rescue => e
+        Puppet.debug("Could not retrieve raw SID bytes from '#{name}': #{e.message}")
       end
 
       raw_sid_bytes ? Principal.lookup_account_sid(raw_sid_bytes) : Principal.lookup_account_name(name)
-    rescue
+    rescue => e
+      Puppet.debug("#{e.message}")
       (allow_unresolved && raw_sid_bytes) ? unresolved_principal(name, raw_sid_bytes) : nil
     end
     module_function :name_to_principal

spec/unit/util/windows/sid_spec.rb

@@ -158,6 +158,12 @@
       # this works in French Windows, even though the account is really AUTORITE NT\\Syst\u00E8me
       expect(subject.name_to_principal('NT AUTHORITY\SYSTEM').sid).to eq(sid)
     end
+
+    it "should print a debug message on failures" do
+      expect(Puppet).to receive(:debug).with(/Could not retrieve raw SID bytes from 'NonExistingUser'/)
+      expect(Puppet).to receive(:debug).with(/No mapping between account names and security IDs was done/)
+      subject.name_to_principal('NonExistingUser')
+    end
   end
 
   context "#ads_to_principal" do