ceph_objectstore_tool: Add utility routine get_osdmap()

Signed-off-by: David Zafman <dzafman@redhat.com>
(cherry picked from commit b3021b0)

Conflicts:
	src/tools/ceph_objectstore_tool.cc

src/tools/ceph_objectstore_tool.cc

@@ -760,6 +760,21 @@ int export_files(ObjectStore *store, coll_t coll)
   return 0;
 }
 
+int get_osdmap(ObjectStore *store, epoch_t e, OSDMap &osdmap)
+{
+  bufferlist bl;
+  bool found = store->read(
+      coll_t::META_COLL, OSD::get_osdmap_pobject_name(e), 0, 0, bl) >= 0;
+  if (!found) {
+    cerr << "Can't find OSDMap for pg epoch " << e << std::endl;
+    return ENOENT;
+  }
+  osdmap.decode(bl);
+  if (debug)
+    cerr << osdmap << std::endl;
+  return 0;
+}
+
 //Write super_header with its fixed 16 byte length
 void write_super()
 {