Fixed the trailing whitespace support in configuration file

| Q               | A
| --------------- | ---
| Bug fix?        | yes
| New feature?    | no
| BC breaks?      | no
| Deprecations?   | no
| Tests pass?     | yes
| Related tickets | #33
| License         | GNU GPLv3

The commit 7749d13f7ef07d9a4f846efe469a2e6fce2ae152 introduce this bug.