This patch renames+moves the net_handle_fd_param() caller used to
obtain a file descriptor from either qemu_parse_fd() (the normal case)
or from monitor_get_fd() (migration case) into a generically prefixed
monitor_handle_fd_param() to be used by vhost-scsi code.

Also update net/[socket,tap].c consumers to use the new prefix.
Reported-by: NMichael S. Tsirkin <mst@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>