(#21971) Fixes PathPattern's usage of Dir.glob for Windows

Dir.glob seems to perform an impilicit to_s on what is passed.  Except
on Windows.  This change explicitly converts Pathname to a String, so we
don't have any surprises.

lib/puppet/file_system/path_pattern.rb

@@ -31,7 +31,7 @@ def prefix_with(prefix)
     end
 
     def glob
-      Dir.glob(pathname)
+      Dir.glob(pathname.to_s)
     end
 
     def to_s

spec/unit/module_spec.rb

@@ -403,40 +403,40 @@
   end
 
   it "should return all manifests matching the glob pattern" do
-    Dir.expects(:glob).with(Pathname.new(@fq_glob_with_extension)).returns(%w{foo bar})
+    Dir.expects(:glob).with(@fq_glob_with_extension).returns(%w{foo bar})
     FileTest.stubs(:directory?).returns false
 
     @mod.match_manifests(@pq_glob_with_extension).should == %w{foo bar}
   end
 
   it "should not return directories" do
-    Dir.expects(:glob).with(Pathname.new(@fq_glob_with_extension)).returns(%w{foo bar})
+    Dir.expects(:glob).with(@fq_glob_with_extension).returns(%w{foo bar})
 
     FileTest.expects(:directory?).with("foo").returns false
     FileTest.expects(:directory?).with("bar").returns true
     @mod.match_manifests(@pq_glob_with_extension).should == %w{foo}
   end
 
   it "should default to the 'init' file if no glob pattern is specified" do
-    Dir.expects(:glob).with(Pathname.new("/a/manifests/init.{pp,rb}")).returns(%w{/a/manifests/init.pp})
+    Dir.expects(:glob).with("/a/manifests/init.{pp,rb}").returns(%w{/a/manifests/init.pp})
 
     @mod.match_manifests(nil).should == %w{/a/manifests/init.pp}
   end
 
   it "should return all manifests matching the glob pattern in all existing paths" do
-    Dir.expects(:glob).with(Pathname.new(@fq_glob_with_extension)).returns(%w{a b})
+    Dir.expects(:glob).with(@fq_glob_with_extension).returns(%w{a b})
 
     @mod.match_manifests(@pq_glob_with_extension).should == %w{a b}
   end
 
   it "should match the glob pattern plus '.{pp,rb}' if no extention is specified" do
-    Dir.expects(:glob).with(Pathname.new("/a/manifests/yay/foo.{pp,rb}")).returns(%w{yay})
+    Dir.expects(:glob).with("/a/manifests/yay/foo.{pp,rb}").returns(%w{yay})
 
     @mod.match_manifests("yay/foo").should == %w{yay}
   end
 
   it "should return an empty array if no manifests matched" do
-    Dir.expects(:glob).with(Pathname.new(@fq_glob_with_extension)).returns([])
+    Dir.expects(:glob).with(@fq_glob_with_extension).returns([])
 
     @mod.match_manifests(@pq_glob_with_extension).should == []
   end