import-hg: Update location for hg-fast-export

The canonical location for the hg-fast-export tool has been on gihub
since 2011.

Author: frej

book/09-git-and-other-scms/sections/import-hg.asc

@@ -5,7 +5,7 @@ Since Mercurial and Git have fairly similar models for representing versions, an
 
 [source,console]
 ----
-$ git clone http://repo.or.cz/r/fast-export.git /tmp/fast-export
+$ git clone https://github.com/frej/fast-export.git
 ----
 
 The first step in the conversion is to get a full clone of the Mercurial repository you want to convert: