make more room because ELF is bigger

src/etc/etc.vax/disktab

@@ -1,4 +1,4 @@
-#	$OpenBSD: disktab,v 1.15 2012/04/26 15:54:54 deraadt Exp $
+#	$OpenBSD: disktab,v 1.16 2013/07/16 17:31:39 deraadt Exp $
 
 bootroot|fake-type used in install boot:\
 	:ty=fake:se#512:nt#1:rm#10:ns#512:nc#1:\
@@ -24,7 +24,7 @@ floppy|floppy3|3in|3.5in High Density Floppy:\
 	:pc#2880:oc#0:
 
 isoroot:\
-	:ty=fake:se#512:nt#11:ns#33:rm#3600:nc#1700:\
-	:pa#617100:oa#0:ba#8192:fa#1024:ta=4.2BSD:\
-	:pc#617100:oc#0:
+	:ty=fake:se#512:nt#11:ns#33:rm#3600:nc#2200:\
+	:pa#798600:oa#0:ba#8192:fa#1024:ta=4.2BSD:\
+	:pc#798600:oc#0: