dir.c: DOTMATCH to current directory

* dir.c (glob_helper): don't skip current directories if FNM_DOTMATCH
  is given.  [ruby-core:53108] [Bug #8006]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43385 b2dd03c8-39d4-4d8f-98ff-823fe69b080e