always close fd `i' in readtimezone, even if there's an error.
also eliminate a bunch of gotos.

Notes:
Mon Apr 10 11:20:22 EDT 2006 rsc
    since the goto can't go away entirely i'm
    inclined to leave the if()s as they are.
    it's going to compile into the same code.
    
    i did fix the fd leak.  thanks.


Reference: /n/sources/patch/applied/readtimezone-fd-leak
Date: Mon Apr 10 02:48:13 CES 2006
Signed-off-by: geoff@collyer.net
Reviewed-by: rsc

--- /sys/src/libc/9sys/ctime.c	Mon Apr 10 02:46:42 2006
+++ /sys/src/libc/9sys/ctime.c	Mon Apr 10 02:46:39 2006
@@ -216,20 +216,13 @@
 	int i;
 
 	memset(buf, 0, sizeof(buf));
-	i = open("/env/timezone", 0);
-	if(i < 0)
-		goto error;
-	if(read(i, buf, sizeof(buf)) >= sizeof(buf))
-		goto error;
-	close(i);
 	p = buf;
-	if(rd_name(&p, timezone.stname))
-		goto error;
-	if(rd_long(&p, &timezone.stdiff))
-		goto error;
-	if(rd_name(&p, timezone.dlname))
-		goto error;
-	if(rd_long(&p, &timezone.dldiff))
+	i = open("/env/timezone", 0);
+	if(i < 0 || read(i, buf, sizeof(buf)) >= sizeof(buf) ||
+	    rd_name(&p, timezone.stname) ||
+	    rd_long(&p, &timezone.stdiff) ||
+	    rd_name(&p, timezone.dlname) ||
+	    rd_long(&p, &timezone.dldiff))
 		goto error;
 	for(i=0; i<TZSIZE; i++) {
 		if(rd_long(&p, &timezone.dlpairs[i]))
@@ -237,8 +230,9 @@
 		if(timezone.dlpairs[i] == 0)
 			return;
 	}
-
 error:
+	if (i >= 0)
+		close(i);
 	timezone.stdiff = 0;
 	strcpy(timezone.stname, "GMT");
 	timezone.dlpairs[0] = 0;