directory /var/cache/swift /srv/node should be created.

For multiple node swift cluster setup, these directories should be
created in the setup steps. Otherwise, when start up storage servers
there will be errors. The error messages won't tell if it is because
of missing the directory.

Change-Id: I67d74abb7743b76739b5e747d6dcbd3214b00774
Fixes: bug #1158519