Only add the IPcomp header if crypto reported success and we have a lower payload size.  Before we had always added the header, no matter if we actually send out compressed data or not.
Only add the IPcomp header if crypto reported success and we have a lower
payload size.  Before we had always added the header, no matter if we
actually send out compressed data or not.

With this, after the opencrypto/deflate changes, IPcomp starts to work
apart from edge cases.  Leave it disabled by default until those are
fixed as well.

PR:		kern/123587
MFC after:	5 days

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase