Merge git://git.bogomips.org/git-svn

* git://git.bogomips.org/git-svn:
  Move initialization of Git::SVN variables into Git::SVN.
  Extract Git::SVN from git-svn into its own .pm file.
  Prepare Git::SVN for extraction into its own file.
  Extract some utilities from git-svn to allow extracting Git::SVN.
  perl: detect new files in MakeMaker builds
  The Makefile.PL will now find .pm files itself.
  Don't lose Error.pm if $@ gets clobbered.
  Quiet warning if Makefile.PL is run with -w and no --localedir