Fix repo copy

[jreidinger]

Problem

The target system is missing repositories from insts-sys. Also cache is cold and needs to be redownloaded for zypp.

Solution

Copy all needed stuff from libzypp. There is one place where it do double copy, which is credentials that are created by suseconnect and then all credentials from libzypp. But this inefficiency is just small and do not hurt. ( Can be removed after discussion with scc guys about not reading scc credentials from target root ).
Also add logic to not remove repositories managed by services ( if not done, user have to manually force refresh services ).

Testing

• Tested manually using openqa proxy which works like a charm with real SLES 16.1.

[coveralls]

coverage: 73.629%. remained the same
when pulling ae66008 on fix_repo_copy
into efc3a49 on master.