oc: Fix internal EntryIds properties on multidomain

PidTag*EntryId properties were not being generated (which contain
the email address and so on). Functionality on Outlook clients like
"Reply All" were not working because of this (probably a lot more
stuff related with email addresses).

With multidomain support enabled outlook clients will use full email
address (e.g. user@domain.com) as login.

This change is needed because we were performing ldap queries on samdb
using (sAMAccountName=UIDFieldName), being UIDFieldName the parameter
configured in sogo.conf for that source. In multidomain environment
this field could be `sAMAccountName` but it could not. Actually the
more logical scenario will be to use `uid` field here (which will be
just `user`, without the `@domain.com` part).

SOGoUserManager will return `sAMAccountName` if the contact has it
(in Outlook environment that means always) so it can (and must) be
used to query samdb in MAPIStoreSamDBUtils properly.

TL;DR: use sAMAccoutName instead of uid to query samdb

OpenChange/MAPIStoreSamDBUtils.m

@@ -96,8 +96,11 @@ MAPIStoreInternalEntryId (struct ldb_context *samCtx, NSString *username)
       [entryId appendUInt8: 0]; // end of string
     }
   else
-    entryId = nil;
- 
+    {
+      NSLog (@"Error trying to generate EntryId for `%@`", username);
+      entryId = nil;
+    }
+
   return entryId;
 }