Made some more args optional

[siad007]

Related to #1034

[codecov]

Codecov Report

Merging #1059 into master will increase coverage by <.01%.
The diff coverage is 66.66%.

@@             Coverage Diff              @@
##             master    #1059      +/-   ##
============================================
+ Coverage     46.65%   46.65%   +<.01%     
- Complexity    10032    10034       +2     
============================================
  Files           505      505              
  Lines         24464    24468       +4     
============================================
+ Hits          11413    11415       +2     
- Misses        13051    13053       +2

Impacted Files	Coverage Δ	Complexity Δ
classes/phing/types/PearPackageFileSet.php	79.48% <66.66%> (-3.37%)	13 <6> (+2)

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