mgr/cephadm: add empty line after param list in docstring

mgr/cephadm: add empty line after param list in docstring

this helps to silence the warning from sphinx, like

src/pybind/mgr/orchestrator/_interface.py:docstring of orchestrator._interface.Orchestrator.remove_osds:9: WARNING: Field list ends without a blank line; unexpected unindent.

Signed-off-by: Kefu Chai <tchaikov@gmail.com>
(cherry picked from commit d9b8e38e3dfe8e6eec6d56ee934c4632de46fc68)

 Conflicts:
	src/pybind/mgr/orchestrator/_interface.py
		- `:param zap:` did not exist in Octopus; removed
		   this from the param list.