- Use m_getcl(), m_get(), and m_gethdr() rather than the older macros for

- Use m_getcl(), m_get(), and m_gethdr() rather than the older macros for
  alloc'ing mbufs so that there is less error handling required.
- Go ahead and account for the data space in the first mbuf before entering
  the loop to alloc more mbuf's.  This simplifies the loop logic and avoids
  confusing Coverity.

CID:		817
Reviewed by:	sam
Tested by:	pjd
Found by:	Coverity Prevent (tm)