domain_setmaxmem takes an int, not a long, for the maxmem_kb parameter. The

domain_setmaxmem takes an int, not a long, for the maxmem_kb parameter.  The
underlying xc_domain_setmaxmem already took an unsigned int, and
PyArg_ParseTupleAndKeywords call was only parsing an int, so there is no way
that longer values would get through here in any case.  Fixing the documentation
and the local variable is the best solution, until someone decides that we need
to support maxmem values greater than 2TiB.

Signed-off-by: Ewan Mellor <ewan@xensource.com>