engine: remove unnecessary parameters from VBOB

currVlan and networkVlan are passed and initilaized through some methods in
VBOB. But they are not actually used anywhere.

Change-Id: I252f1e789a346d045afdf32d638c163abcbe03c1
Bug-Url: https://bugzilla.redhat.com/1091863
Bug-Url: https://bugzilla.redhat.com/999975
Signed-off-by: Alona Kaplan <alkaplan@redhat.com>