Fix ports in swift-ring-builder commands

Fix a typo in the port numbers in the ring creation example.

Change-Id: Idd482ad059393c2e29e44a14f1cc1ff170685cf4
backport: havana
Closes-Bug: #1302795
(cherry picked from commit b2ea8750356cdade00630c3a82d80e70dcb3eb84)