LU-13819 build: Update ZFS version to 0.8.4

LU-13819 build: Update ZFS version to 0.8.4

Changes from 0.8.3

* Add missing zfs_refcount_destroy() in key_mapping_rele() #10246
* Linux 5.7 compat: blk_alloc_queue() #10181 #10187
* Prefix struct rangelock #9534
* Fix icp include directories for in-tree build #10021
* ICP: gcm-avx: Support architectures lacking the MOVBE
  instruction #10029
* ICP: Improve AES-GCM performance #9749
* Bugfix/fix uio partial copies #8673 #10148
* Prevent deadlock in arc_read in Linux memory reclaim
  callback #9987
* Fix infinite scan on a pool with only special allocations
  #10106 #8694
* Static symbols exported by ICP #9791
* Linux 5.6 compat: struct proc_ops #9961
* Linux 5.6 compat: timestamp_truncate() #9956 #9961
* Linux 5.6 compat: ktime_get_raw_ts64() #10052 #10064
* Linux 5.6 compat: time_t #10052 #10064
* Fix static data to link with -fno-common #9943
* zfs_get: change time format string from %k to %H #10090 #10153
* Deprecate deduplicated send streams #7887 #10117
* Fix zfs-functions packaging bug
* initramfs: Eliminate substitutions
* Delete built init scripts in make clean
* Restore :: in Makefile.am #9210
* Make init scripts depend on Makefile
* Systemd mount generator: don't fail keyload from file if
  already loaded #10103
* Systemd mount generator: Generate noauto units; add control
  properties #9649
* Systemd mount generator: Silence shellcheck warnings #9649
* Fix CONFIG_MODULES=no Linux kernel config #9887 #10063
* Linux 5.5 compat: blkg_tryget() #9745 #10072
* zfs-mount-generator: Fix escaping for / #9970
* Missed wakeup when growing kmem cache #9989
* Order zfs-import-*.service after multipathd #9863
* Avoid here-documents in systemd mount generator #9802

Signed-off-by: Nathaniel Clark <nclark@whamcloud.com>
Change-Id: I3a270376e05d466eeb8e8ba93d7c4aa0d2546ae6
Reviewed-on: https://review.whamcloud.com/39507
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>