Rewrite code to avoid triggering warning about casting param to free()
Rewrite code to avoid triggering warning about casting param to free()

Since free() takes a void* parameters do not need to be cast.

The existing code here is actally fine, but it trips up the
syntax-check rule, so tweak it to an equivalent construct
which passes the syntax check

dezelin/spice,Fantu/spice,freedesktop-unofficial-mirror/spice__spice,elmarco/spice,alon/spice-server,freedesktop-unofficial-mirror/spice__spice,dezelin/spice,freedesktop-unofficial-mirror/spice__spice,elmarco/spice,SPICE/spice,dezelin/spice,freedesktop-unofficial-mirror/spice__spice,mathslinux/spice,mathslinux/spice,ya-mouse/spice,Fantu/spice,fgouget/spice,mathslinux/spice,dezelin/spice,Fantu/spice,alon/spice-server,elmarco/spice,SPICE/spice,ya-mouse/spice,SPICE/spice,mathslinux/spice,fgouget/spice,ya-mouse/spice,dezelin/spice,elmarco/spice,alon/spice-server,freedesktop-unofficial-mirror/spice__spice,Fantu/spice,alon/spice-server,elmarco/spice,fgouget/spice,alon/spice-server,fgouget/spice,mathslinux/spice