Change the location from where we try to pull the outer headers

The function that pulls outer headers assumes that the packet data
points at layer 2 header. While this is true in case of ubuntu, the
commit that made this assumption did not reposition the call for
Centos, resulting in pull failures.

Change-Id: Iaae280817820feb87a525db8c028bcba4e905bb1
Closes-BUG: #1393730