Resolves: bug 476127

Bug Description: rhds80 seg fault - pass sync - entry missing userPassword ?
Reviewed by: nkinder (Thanks!)
Fix Description: The fix is pretty obvious - just make sure we don't deref a NULL.  The reason for the NULL is due to a sequence of more than one modify for the userPassword attribute, where one of the mods is a replace with no value or a delete of the attribute.  The bug has the details about how to reproduce.  One thing I don't know is what client is generating this sequence of operations . . .
Platforms tested: RHEL5
Flag Day: no
Doc impact: no
QA impact: should be covered by regular nightly and manual testing
New Tests integrated into TET: none

ldap/servers/plugins/replication/windows_protocol_util.c

@@ -1812,7 +1812,8 @@ windows_map_mods_for_replay(Private_Repl_Protocol *prp,LDAPMod **original_mods,
 			} else 
 			{
 				/* password mods are treated specially */
-				if (0 == slapi_attr_type_cmp(attr_type, PSEUDO_ATTR_UNHASHEDUSERPASSWORD, SLAPI_TYPE_CMP_SUBTYPE) )
+				if ((0 == slapi_attr_type_cmp(attr_type, PSEUDO_ATTR_UNHASHEDUSERPASSWORD, SLAPI_TYPE_CMP_SUBTYPE)) &&
+					mod && mod->mod_bvalues && mod->mod_bvalues[0] && mod->mod_bvalues[0]->bv_val)
 				{
 					char *password_value = NULL;
 					password_value = mod->mod_bvalues[0]->bv_val;