(#11276) Expand Dir.pwd

On Windows, Dir.pwd returns a path with backslashes, which confuses the
relative path from, since it doesn't know that 'C:/' and 'C:\' are the
same.

This commit simply expands Dir.pwd which results in forward slashes.

Author: joshcooper

lib/puppet/module_tool/applications/builder.rb

@@ -18,7 +18,7 @@ def run
         Puppet.notice "Building #{@path} for release"
         tar
         gzip
-        relative = Pathname.new(File.join(@pkg_path, filename('tar.gz'))).relative_path_from(Pathname.new(Dir.pwd))
+        relative = Pathname.new(File.join(@pkg_path, filename('tar.gz'))).relative_path_from(Pathname.new(File.expand_path(Dir.pwd)))
 
         # Return the Pathname object representing the path to the release
         # archive just created. This return value is used by the module_tool