Fixing bad behavior in IOUtil.deletePaths

[lbergelson]

• The method IOUtil.deletePaths(Iterable<Path>) had pathological behavior.

  • A Path is an Iterable<Path> which iterates over the subpaths in the Path. Therefore, this version was binding instead of the varargs version that takes Path... Then the method would try to delete all of the subpaths in the path which doesn't delete the intended target and could delete random files.
  • This is obviously bad behavior. Fixed by adding an explicit check to see if it's called with a single Path.
  • Extracted a new method deletePath which is used for deleting a single path.

• Fixes #https://github.com/samtools/htsjdk/issues/1414

[codecov-io]

Codecov Report

Merging #1416 into master will increase coverage by 0.003%. The diff coverage is 100%.

@@               Coverage Diff               @@
##              master     #1416       +/-   ##
===============================================
+ Coverage     68.124%   68.127%   +0.003%     
- Complexity      8379      8381        +2     
===============================================
  Files            573       573               
  Lines          33982     33985        +3     
  Branches        5668      5668               
===============================================
+ Hits           23150     23153        +3     
  Misses          8643      8643               
  Partials        2189      2189

Impacted Files	Coverage Δ	Complexity Δ
src/main/java/htsjdk/samtools/util/IOUtil.java	58.413% <100%> (+0.302%)	120 <5> (+2)	:arrow_up:
...ain/java/htsjdk/samtools/util/DiskBackedQueue.java	64.22% <100%> (ø)	29 <0> (ø)	:arrow_down: