Merge pull request #39 from Juniper/fix

Fix(cherry picked from commit 830db4a93903ca80633269b5bda1a92e7bbf9f14)
- Cosmetic changes
- During soft reset, the first thing that happens in vrouter is to shut down
all interfaces and thus making sure that traffic does not enter or exit vrouter.
Once that step is done, to free vrouter data structures there no longer is a need
to wait for all packet paths to stop using those data structures. So, put conditional
waits.
- Use call_rcu to free mirror meta entries rather than the synchronous delay operation.
- Fix a memory corruption issue that will be hit when packets were flushed from the flow entry.
- dhcp packets are trapped only if they are part of the request and
are originated from a VM