network: Fix missing or improper include guard in headers

network: Fix missing or improper include guard in headers

Use an include guard in headers to ensure the header is not included
more than once. Make the header guard match its file name.

Also, cpp files should include their own headers first (but below config.h)

Change-Id: Iecf5da23c0f8e6d457f67657b88ef7557bde9669
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>