mon/Monitor.cc: init scrub_version with 0 in constructor

CID 1019623 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
  uninit_member: Non-static class member "scrub_version" is not
  initialized in this constructor nor in any functions that it calls.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
os/ObjectStore.cc: don't fallthrough after OP_OMAP_RMKEYRANGE

CID 1054829 (#1 of 1): Missing break in switch (MISSING_BREAK)
  unterminated_case: This case (value 37) is not terminated by a
  'break' statement.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
rgw/rgw_metadata.cc: fix possible null dereferencing

CID 1054827 (#1 of 1): Dereference after null check (FORWARD_NULL)
  var_deref_model: Passing null pointer "objv_tracker->read_version"
  to function "obj_version::operator =(obj_version const &)", which
  dereferences it.

Moved affected 2 cases into the block checking for objv_tracker

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
rgw/rgw_metadata.h: init cur_shard in LogListCtx with 0

CID 1054868 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
  uninit_member: Non-static class member "cur_shard" is not
  initialized in this constructor nor in any functions that it calls.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
Merge pull request #465 from dalgaaf/wip-da-CID-2

Fix some more CID issues

Reviewed-by: Sage Weil <sage@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>