Replace @VERSION@ with a proper version before calling spectool

spectool internally calls rpm. Newer rpm does more checks on spec file
including checking that version make sense so it does not accept anymore
'@' in version.
Patch version file while sending to spectool.
spectool should not be patched as is a tools copied from another package.

Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>