[context] Use installonly_limit from global config (RhBug:1256108)
[context] Use installonly_limit from global config (RhBug:1256108)

The patch uses the global configuration option "installonly_limit".
The option was ignored and hardcoded value 3 was used before the patch.

Closes: #857
Approved by: m-blaha

rpm-software-management/libdnf,rpm-software-management/libhif,rpm-software-management/libhif,hughsie/libhif,rpm-software-management/libdnf,hughsie/libhif,rpm-software-management/libdnf,rpm-software-management/libhif,hughsie/libhif,hughsie/libhif,rpm-software-management/libdnf,rpm-software-management/libhif