Ensure there is a slash in the object prefix

zuul sends the destination address without a trailing slash.
This is because the LOG_PATH does not contain one.

Check to see if we need to add a slash to object paths before
pushing to swift

Change-Id: I3e43c4ea266b57028fcaf9aa5fd09f1f5e37c306
Merge "Ensure there is a slash in the object prefix"