Merge pull request #7503 from tchaikov/wip-cmake-spdk

build: spdk submodule; cmake

Reviewed-by: Kefu Chai <kchai@redhat.com>

diff --cc CMakeLists.txt
Simple merge

diff --cc configure.ac
Simple merge

diff --cc src/CMakeLists.txt
Simple merge

diff --cc src/Makefile-env.am
Simple merge

diff --cc src/Makefile.am
Simple merge

diff --cc src/os/bluestore/NVMEDevice.cc
Simple merge