Replaced the allocation and deallocation of fuse_req structs
using calloc()/free() call pairs to a GLib's g_try_new0()
and g_free().

Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20210420154643.58439-2-ma.mandourr@gmail.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>