Add trusted domain range objectclass when using idrange-mod

When modifing the idrange, one was able to add ipa NT trusted
AD domain sid without objectclass ipatrustedaddomainrange being
added. This patch fixes the issue.

ipalib/plugins/idrange.py

@@ -533,6 +533,11 @@ class idrange_mod(LDAPUpdate):
                 # perform this check only if the attribute was changed
                 self.obj.validate_trusted_domain_sid(
                     entry_attrs['ipanttrusteddomainsid'])
+
+           # Add trusted AD domain range object class, if it wasn't there
+            if not 'ipatrustedaddomainrange' in old_attrs['objectclass']:
+                entry_attrs['objectclass'].append('ipatrustedaddomainrange')
+
         else:
             # secondary base rid must be set if and only if base rid is set
             if in_updated_attrs('ipasecondarybaserid') !=\