Encryption patch follow-up

* PBKDF2 implementation changed to OpenSSL implementation.

* HKDF implementation moved to its own file and tests
  added to ensure correctness.

* Removed libzfs's now unnecessary dependency on libzpool
  and libicp.

* Ztest can now create and test encrypted datasets. This is
  currently disabled until issue #6526 is resolved, but
  otherwise functions as advertised.

* Several small bug fixes discovered after enabling ztest
  to run on encrypted datasets.

* Fixed coverity defects added by the encryption patch.

* Updated man pages for encrypted send / receive behavior.

* Fixed a bug where encrypted datasets could receive
  DRR_WRITE_EMBEDDED records.

* Minor code cleanups / consolidation.

Signed-off-by: Tom Caputi <tcaputi@datto.com>

lib/libzpool/Makefile.am

@@ -68,6 +68,7 @@ KERNEL_C = \
 	dsl_destroy.c \
 	dsl_userhold.c \
 	edonr_zfs.c \
+	hkdf.c \
 	fm.c \
 	gzip.c \
 	lzjb.c \