OpenZFS 1300 - filename normalization doesn't work for removes

Authored by: Kevin Crowe <kevin.crowe@nexenta.com>
Reviewed by: Yuri Pankov <yuri.pankov@nexenta.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>

OpenZFS-issue: https://www.illumos.org/issues/1300
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/8f1750d
Closes #5725 

Porting notes:
- zap_micro.c: all `MT_EXACT` are replaced by `0`

include/sys/zap_impl.h

@@ -18,10 +18,12 @@
  *
  * CDDL HEADER END
  */
+
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
  * Copyright (c) 2013, 2016 by Delphix. All rights reserved.
+ * Copyright 2017 Nexenta Systems, Inc.
  */
 
 #ifndef	_SYS_ZAP_IMPL_H
@@ -188,6 +190,7 @@ typedef struct zap_name {
 	int zn_key_norm_numints;
 	uint64_t zn_hash;
 	matchtype_t zn_matchtype;
+	int zn_normflags;
 	char zn_normbuf[ZAP_MAXNAMELEN];
 } zap_name_t;