Changes

pySim.esim.saip: Fix docstring warnings:

this fixes the following two warnings:

pySim/esim/saip/__init__.py:docstring of pySim.esim.saip.FsNode.walk:1: WARNING: Inline strong start-string without end-string. [docutils]
pySim/esim/saip/__init__.py:docstring of pySim.esim.saip.FsNodeDF.walk:1: WARNING: Inline strong start-string without end-string. [docutils]

Change-Id: Id7debf9296923b735f76623808cee68967a1ece7