Correct bug in payload reallocation function

When using the rmr_realloc_payload() function with the copy
flag set, it was possible to copy a short length of data,
or none at all.  This change corrects the miscomputed length
to copy.

Signed-off-by: E. Scott Daniels <daniels@research.att.com>
Change-Id: I01a98fa66ab69d5f11a792463bc04b73209f098b
10 files changed