Declare non-initialized variable in _create_manifests

Declare the variable pkg, that was being declared after conditional
statements. So, if the conditional statement was not confirmed, will be
raise UndeclaredReference. This fix avoid it.

Change-Id: I4c095c03c0f773f54ae263d57ce979b9a1b5e632
Signed-off-by: Ramon Medeiros <ramonn@linux.vnet.ibm.com>