Change eth0 to eth2 in Ops Guide Networking Diagram

1) Built a new version of figure 12.2 replacing eth0 with eth2
and clearing up shape overlaps from the original diagram.
2) Changed references to the internet facing eth0 to eth2
in the text corresponding to figure 12.2.

Change-Id: Iedbcb1de123627158a67dd97e820158d844be9f2
backport:none
Closes-Bug: #1372516
Merge "Change eth0 to eth2 in Ops Guide Networking Diagram"