MetadataLocationObtainer has undocumented confusing behavior

While reviewing #2861, I noticed that the `more` field wasn't really used for much. It was just used for one additional lookup. However, the value of `more` was never assigned again. It looked like this was originally supposed to be part of a loop and the `more` value being true kept it in the loop. However, looking at this code further, I can't tell what any of it is doing. It looks like the `if` should be a `while` loop, but this is not clear. Perhaps only one additional lookup needs to be done if `more` is true, but there are no comments explaining why this would be the case, and it's not obvious to me. Some comments in here would be really nice, and if there is a bug and this should be a loop, that should be fixed.

https://github.com/apache/accumulo/blob/6d3aeccd8e86853bb8cf88b7590673787e127d0a/core/src/main/java/org/apache/accumulo/core/metadata/MetadataLocationObtainer.java#L114-L123

Read core/src/main/java/org/apache/accumulo/core/metadata/MetadataLocationObtainer.java around lines 114-123, then compare the behavior with the context from issue #2861. Determine why `more` is used for the additional lookup and whether one lookup or repeated looping is intended. Done means the behavior is explained with comments, or the behavior is corrected if the investigation confirms a bug.

Written by the indexing model from the issue text.