add rocksdb support

Signed-off-by: xinxin shu <xinxin.shu@intel.com>
add rocksdb submodule
get a stable rocksdb (3.0)

Signed-off-by: xinxin shu <xinxin.shu@intel.com>
add --with-librocksdb-static configure options

with this options, ceph will build rocksdb from submodule

Signed-off-by: xinxin shu <xinxin.shu@intel.com>
rocksdb backend optimization

Signed-off-by: xinxin shu <xinxin.shu@intel.com>
rocksdb: update submodule makefile

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
do_autogen.sh: build with static librocksdb

Signed-off-by: Sage Weil <sage@redhat.com>
rocksdb: require less shiny autoconf

precise has 2.59

Signed-off-by: Sage Weil <sage@redhat.com>
configure: verify c++11 is present for rocksdb

Signed-off-by: Sage Weil <sage@redhat.com>
Makefile: include rocksdb in dist tarball always

Signed-off-by: Sage Weil <sage@redhat.com>
configure: enable static rocksdb if check and c++11

Signed-off-by: Sage Weil <sage@redhat.com>
add rocksdb bz2 dep

Signed-off-by: Sage Weil <sage@redhat.com>
debian, rpm: build require bzip2 dev

Signed-off-by: Sage Weil <sage@redhat.com>
debian, rpm: build rocksdb statically if we can

Signed-off-by: Sage Weil <sage@redhat.com>
autogen.sh: debug with -x

Signed-off-by: Sage Weil <sage@redhat.com>
rocksdb: -Wno-portability

Signed-off-by: Sage Weil <sage@redhat.com>
Merge branch 'wip-rocksdb'