lookup tables Data Adapter Info/Mouseover for errors flips Message

## Expected Behavior
When some Error in the Data Adapter is given, the mouseover should show what error is found.

## Current Behavior

Sometime the error show the count and then changed to the error part without a reason.

## Possible Solution
Show the error message of the parser not the count that ppl. are able to correct that faster.

Show empty line as error **empty line** and not just the letter 1 or ignore them.

## Context

This Lookup CSV contains two errors, one double entry for the same key and one blank line that is not ignored in the middle.

Technical it is correct to say a blank line is an error, but ppl might use the blank line to make it more human readable.

## Environment
* Graylog Version: 2.3.0 rc.1