Stock venti startup leaves venti without reasonable sizes for the various indices. 
This change will invoke it with something that will guarantee reasonable behavior. 
Without this change, venti seems to go quite crazy, and on my machine, was
generating 10,000 system calls/second. 

Notes:
Mon Nov 30 11:41:17 EST 2009 geoff
    as we agreed, we'll do this instead with better venti defaults.


Reference: /n/sources/patch/sorry/reasonable-venti-defaults-at-boot
Date: Mon Nov 30 05:34:44 CET 2009
Signed-off-by: rminnich@gmail.com
Reviewed-by: geoff

--- /sys/src/9/boot/local.c	Mon Nov 30 05:26:29 2009
+++ /sys/src/9/boot/local.c	Mon Nov 30 05:26:27 2009
@@ -224,7 +224,7 @@
 				f[2] = "tcp!127.1!8000";
 			}
 			configloopback();
-			run("/boot/venti", "-c", f[0], "-a", f[1], "-h", f[2], 0);
+			run("/boot/venti", "-c", f[0], "-m", "20", "-a", f[1], "-h", f[2], 0);
 			/*
 			 * If the announce address is tcp!*!foo, then set
 			 * $venti to tcp!127.1!foo instead, which is actually dialable.