ifreload: disable ignore_prio and ignore_startmode by default

Introduce compile time flag NI_TEST_HACKS to enable them
in order to facilitate testing
ifup,ifreload: Remove ifpolicy option

ifpolicy was a aliast to ifconfig - no longer needed.
Merge pull request #238 from pwieczorkiewicz/ifreload-ignore

Clean up ifup and ifreload client options
Merge branch 'master' into testing
client: do not mix shared with exlusive references (bnc#877776)

An exclusive reference (master device reference) conflicts with
other exclusive references, but not with shared (lower device).