Make sctp buffers big enough for images

We had multiple problems.
  1) kernel buffers were too small so the kernel was delivering partial
     packets.  Fix was to update the rootfs to increase the buffer size
     and check the parameter.  Secondary fix was to CHECK that received
     packets were the size advertized.
  2) Client wasn't configuring it's buffers to be the right size.
     Configured the socket to make it big enough.

Change-Id: I276e698943aa5714ff2ca8e1ac73d6975d219eb9
diff --git a/aos/network/sctp_server.h b/aos/network/sctp_server.h
index b702aa8..25d81fc 100644
--- a/aos/network/sctp_server.h
+++ b/aos/network/sctp_server.h
@@ -51,8 +51,13 @@
     // Have the kernel give us a factor of 10 more.  This lets us have more than
     // one full sized packet in flight.
     max_size = max_size * 10;
+
+    CHECK_GE(ReadRMemMax(), max_size);
+    CHECK_GE(ReadWMemMax(), max_size);
     PCHECK(setsockopt(fd_, SOL_SOCKET, SO_RCVBUF, &max_size,
                       sizeof(max_size)) == 0);
+    PCHECK(setsockopt(fd_, SOL_SOCKET, SO_SNDBUF, &max_size,
+                      sizeof(max_size)) == 0);
   }
 
  private: