MBUF - Do not limit an objcache common pool to 10 magazines.

MBUF - Do not limit an objcache common pool to 10 magazines.

* An objcache's common magazine pool was limited to 10 in order to return
  memory to the system sooner rather then later.

  This created a situation with the mbuf allocator where high-rate
  mbuf producers (GigE, 10GigE) would sometimes not be able to allocate
  a large enough batch of mbufs and drop packets.  10 magazines x 64 is
  only 640 mbufs.

* Increase the limit from 10 to 1000.

Tested-with: 10GigE setup from Aggelos Economopoulos <aoiko@cc.ece.ntua.gr>