MOSDBoot: fix compatibility with ~argonaut

I revved this message and forgot to set the compat version correctly,
preventing post-change (e.g., bobtail) OSDs from talking to pre-change
(e.g., argonaut) monitors.  This was in b64641c.

Signed-off-by: Sage Weil <sage@inktank.com>
Makefile:  Updates to eliminates warnings, add test for boost system lib.
Makefiles:  ignore the m4 macro directory
Makefiles:  Missing boost library should not be fatal.
Makefile: Improve test for boost system library.
leveldb: fix-up submodule entry.
Makefile: update submodule reference for leveldb.
Makefiles:  Update submodule reference to latestes for leveldb.
autogen.sh:  Create m4 directory for leveldb submodule.
autogen.sh:  On some platforms, the m4 is created earlier.
Makefiles:  Add ar-lib to .gitignore.
Makefile:  Add CRYPTO_C(XX)FLAGS to librdb
cls_rbd: add stripe_unit, stripe_count metadata

* add STRIPINGV2 feature
* add stripe_unit, stripe_count keys
* add accessor methods

Signed-off-by: Sage Weil <sage@inktank.com>
librbd: load striping information when opening image

Silently tolerate an -ENOEXEC or -EINVAL (which means striping is not
present or is not supported by the osd class).

Signed-off-by: Sage Weil <sage@inktank.com>
librbd: allow striping to be specified on image creation

Signed-off-by: Sage Weil <sage@inktank.com>
rbd: allow striping to be specified on image creation

Signed-off-by: Sage Weil <sage@inktank.com>
cls_rbd: fix snap key filtering

Ignore any omap keys that don't begin with "snap_".  We got away with this
previously because it was (lexiographically) the last key for the object.

Signed-off-by: Sage Weil <sage@inktank.com>
librbd: expose image striping properties

Fix C and C++ APIs.

Signed-off-by: Sage Weil <sage@inktank.com>
rbd: show striping parameters with 'info' command

Signed-off-by: Sage Weil <sage@inktank.com>
filer: generalize file_to_extents to take a format string

Allow any format string to be used, so long as it takes a long long
unsigned.

Signed-off-by: Sage Weil <sage@inktank.com>