[exporter/elasticsearch] Fix getLocations()

[rockdaboot]

Fixes getLocations(), random encounter when reading the code.

Problem(s)

1. The code block executed for length > 0 is broken. It should loop from start to start + length but loops from start to length, which only works for start == 0.
2. The code block executed for length == 0 contains a no-op loop.

Solution
Fix the code to work for all values of length and start.
Additionally, the PR moves the check i < profile.LocationTable().Len() out of the loop body.

[carsonip]

do you mind expanding on what's broken (in the changelog and in PR description)? I don't have the domain knowledge around profiles locations

[rockdaboot]

do you mind expanding on what's broken (in the changelog and in PR description)? I don't have the domain knowledge around profiles locations

Added a comment to the PR. You don't need domain knowledge - it is/was just an issue with the logic.

[carsonip]

thanks, now i get it.