Issue title: NGSIv2 In queries a trailing ';' raises error 400
 Issue body: A query like 

```
q=addressLocality==Santander;addressCountry==ESP;
```

now is returning 400 HTTP error. Previous version didn't . We need to decide. I'm in favour of allowing trailing ';' 

 Comments: 
 Comment 0: Yes, this seems to be an error introduced in the complete rewrite of this part.
One trailing ';' should be allowed, but not more than one.

Also, we need a functest to capture this situation.

 Comment 1: Fixed in PR https://github.com/telefonicaid/fiware-orion/pull/2326

{'source': 'GithubIssues', 'repo_name_with_owner': 'telefonicaid/fiware-orion', 'issue_id': 151096661, 'repo_stars': 171.0}