[contrib] Specify boot order in bochsrc.txt

Signed-off-by: Michael Brown <mcb30@ipxe.org>

contrib/vm/bochsrc.txt

@@ -300,6 +300,7 @@ ata3: enabled=0, ioaddr1=0x168, ioaddr2=0x360, irq=9
 #=======================================================================
 #boot: floppy
 #boot: disk
+boot: network, floppy
 
 #=======================================================================
 # CLOCK: