remoteNodeGetFreePages: Don't alloc args.pages.pages_val
    
    There's no one to free() it anyway. Instead, we can just pass the
    provided array pointer directly.
    
    ==20039== 48 bytes in 4 blocks are definitely lost in loss record 658 of 787
    ==20039==    at 0x4C2A700: calloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
    ==20039==    by 0x4EA661F: virAllocN (viralloc.c:191)
    ==20039==    by 0x50386EF: remoteNodeGetFreePages (remote_driver.c:7625)
    ==20039==    by 0x5003504: virNodeGetFreePages (libvirt.c:21379)
    ==20039==    by 0x154625: cmdFreepages (virsh-host.c:374)
    ==20039==    by 0x12F718: vshCommandRun (virsh.c:1935)
    ==20039==    by 0x1339FB: main (virsh.c:3747)
    
    Signed-off-by: Michal Privoznik <mprivozn@redhat.com>