python: bugfix in type signature of python callback
python: bugfix in type signature of python callback

Python callback dp_get_items now returns Vals_Holder instead of Vals
class.

Signed-off-by: Mislav Novakovic <5678c0d5a488e1fbc1213419c52ed0f667208fac@sartura.hr>

morganzhh/sysrepo,morganzhh/sysrepo,morganzhh/sysrepo,morganzhh/sysrepo,morganzhh/sysrepo,morganzhh/sysrepo,morganzhh/sysrepo