pybind/mgr: add a log line to hint why mgr sqlite3 db not ready

Signed-off-by: John Mulligan <[email protected]>

Author: phlogistonjohn

src/pybind/mgr/mgr_module.py

@@ -1323,6 +1323,7 @@ def close_db(self) -> None:
     def open_db(self) -> Optional[sqlite3.Connection]:
         if not self.pool_exists(self.MGR_POOL_NAME):
             if not self.have_enough_osds():
+                self.log.warning('not enough osds to create mgr pool')
                 return None
             self.create_mgr_pool()
         uri = f"file:///{self.MGR_POOL_NAME}:{self.module_name}/main.db?vfs=ceph"