vhd-tool: Update to 0.7.4

Signed-off-by: Euan Harris <euan.harris@citrix.com>
makedeb: Rewrite _sysconfdir to /etc for configuration files

Signed-off-by: Euan Harris <euan.harris@citrix.com>
specs: Rewrite Requires and BuildRequires to one per line

This should reduce merge conflicts in future.

Signed-off-by: Euan Harris <euan.harris@citrix.com>