tools: Adds tests of argument values in engine-manage-domains

Current implementation tests only if required arguments are entered on
command line, but it doesn't test if their values has been entered.
This patch adds test, that if an argument requires value, its value
has to be also entered on command line.

Change-Id: Ie6c41e209539b14b4499f424c54584401b6312e4
Bug-Url: https://bugzilla.redhat.com/927949
Signed-off-by: Martin Perina <mperina@redhat.com>