This patch adds support for L3SPAN to the existing tap as a service
NSXv3 driver.
If the source and destination port are not on the same host,
the mirror session is L3SPAN. Backend supports L3SPAN with
SwitchingProfiles of type PortMirroring. Hence, creation of a
tap-flow will result in creation of a switching profile with the
destination port's IP address and then updates the source port
with this newly created switching profile.
Change-Id: I74ea40f8b9c9d1c343a4d9681c3a9ec77b521b6e
3eb8e148d4