Fix english in GUI labels

[angelorosacewp]

Current Behavior

There is written the word "directoy" in modules/fileshipper/library/Fileshipper/ProvidedHook/Director/ImportSource.php and ' defaults to double quote: "' in the same file, which is not true as the field requires a character

How to reproduce

• Director
• Import data sources
• Add
• under "source type" select Fileshipper
• look at the additional options that pop up

My Environment

• Director Version: 1.5.1
• Icinga 2 version: 2.10.1-1
• Operating System and version: Centos 7
• PHP versions: rh-php71-php-fpm-7.1.8

Comment

This pull request refers to the pull request (https://github.com/Icinga/icingaweb2-module-fileshipper/pull/28) but with suggestions from @Thomas-Gelf

[martialblog]

@Thomas-Gelf This PR can be merged