Delete useless variables assignment

Task resource is not used on PackagesUpdate so there is no need to
assign it.

Signed-off-by: Aline Manera <alinefm@linux.vnet.ibm.com>
Fix issue #430: Properly list packages update on openSUSE systems

getPackagesList() is supposed to return a list of dictionaries in which
dict represents a package to be updates in the format:

{'package_name': <string>, 'version': <string>, 'arch': <string>,
'repository': <string>}

But it was retuning a list of packages names that was breaking all the
update logic.
Fix it by returning the right data format on getPackagesList()

Signed-off-by: Aline Manera <alinefm@linux.vnet.ibm.com>