dont assume that canpage is called spllo. this is a temporary kludge until we get paging ripped out

Reference: /n/atom/patch/applied/canpagehi
Date: Thu May  1 18:30:58 CES 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/nix/port/proc.c	Thu May  1 18:30:58 2014
+++ /sys/src/nix/port/proc.c	Thu May  1 18:30:58 2014
@@ -716,8 +716,9 @@
 {
 	int ok;
 	Sched *sch;
+	Mpl pl;
 
-	splhi();
+	pl = splhi();
 	sch = procsched(p);
 	lock(sch);
 	/* Only reliable way to see if we are Running */
@@ -728,7 +729,7 @@
 	else
 		ok = 0;
 	unlock(sch);
-	spllo();
+	splx(pl);
 
 	return ok;
 }