Use md5 as default hash method again

Older Debian releases are not able to cope with sha256 hashed
passwords and refuse login without any visible or accessible error
message.

This only affects the initially set root password and does not affect
passwords which are later set with the DomU's "passwd" tool.

bin/xen-create-image

@@ -1294,7 +1294,7 @@ sub setupDefaultOptions
     $CONFIG{ 'genpass' }     = 1;
     $CONFIG{ 'genpass_len' } = $default_genpass_len;
     $CONFIG{ 'password' }    = undef;
-    $CONFIG{ 'hash_method' } = 'sha256';
+    $CONFIG{ 'hash_method' } = 'md5';
 
     #
     #  The program to run to create a filesystem.

debian/changelog

@@ -23,6 +23,9 @@ xen-tools (4.5+dev-1) UNRELEASED; urgency=medium
       versions which don't know either (but accept any Foo=Bar parameter
       to "-o"). Allows one to install earlier Debian releases (e.g. Etch)
       with the default configuration again.
+    + Use md5 as default hash method again, to be able to properly set
+      passwords in older releases. Does not affect passwords changed later
+      inside the DomU.
   * Update Vcs-* headers as Gitorious will close its doors in June.
   * Recommend debian-archive-keyring (for installing Debian DomUs on
     derivatives) and ubuntu-archive-keyring (for installing Ubuntu DomUs