dhcp4: add support for additional DHCPv4 request options

For now, push the values from ifcfg to the dhcp4 request structures. We
will use them later.
schema: add additional DHCPv4 options
client: parse additional DHCPv4 options to xml
dhcp: bring link up if not yet in --test mode
bridge: fixed to set port link up (bnc#866860)

Fixed to set bridge ports link up, also if they're already
part of the bridge. Regression of fixes from bnc#862530.
Merge pull request #184 from mtomaschewski/dhcp-test-link-up

dhcp: bring link up if not yet in --test mode
Merge pull request #185 from mtomaschewski/bridge-port-set-link-up
Merge pull request #183 from kmroz/dhcp4-extra-options-rc
compat: correctly init dhcp recover/release lease

Initialize default settings at the right places.
Fixed to not reset global settings while reading
the per-interface settings from suse ifcfg files.
compat: include appconfig.h for wicked defaults
service: explicit before/after ordering (bnc#866732)
rpm: added sysconfig-netconfig require to wicked
Merge branch 'sle12' (bnc#867078,bnc#866732)