Hosts file parser cleanup

[tzaeschke]

This change is 

[codecov]

Codecov Report

Attention: Patch coverage is 71.11111% with 13 lines in your changes are missing coverage. Please review.

Project coverage is 77.40%. Comparing base (382ffe9) to head (2de69f7).

Files	Patch %	Lines
src/main/java/org/scion/internal/DNSHelper.java	75.00%	5 Missing and 2 partials ⚠️
src/main/java/org/scion/ScionAddress.java	50.00%	2 Missing ⚠️
src/main/java/org/scion/ScionService.java	33.33%	1 Missing and 1 partial ⚠️
.../main/java/org/scion/internal/HostsFileParser.java	80.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master      #42      +/-   ##
============================================
- Coverage     77.51%   77.40%   -0.11%     
- Complexity      403      404       +1     
============================================
  Files            26       26              
  Lines          1948     1943       -5     
  Branches        260      259       -1     
============================================
- Hits           1510     1504       -6     
  Misses          327      327              
- Partials        111      112       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.