networking: handle case when ProtocolIFType is None

ProtocolIFType property of LMI_IPAssignmentSetting data can be empty
sometimes. This commit adds a check for it.
networking: fix wrong function for ending test phase

It should fix problem with unfinished tests on buildbot.
networking: explicitly differentiate between IPv4 and IPv6 addresses
Merge pull request #70 from rnovacek/fixes

Various fixes in networking command and script