net: fix dns bug reported on irc.

if suffixes don't work, check for name directly.
also fixes short names like bit.ly when ndots>1.

tested by tossing domain and search lines from /etc/resolv.conf

Fixes #2.

R=agl, agl1
CC=golang-dev
https://golang.org/cl/152048

Author: rsc

src/pkg/net/dnsclient.go

@@ -268,5 +268,16 @@ func LookupHost(name string) (cname string, addrs []string, err os.Error) {
 			return;
 		}
 	}
+
+	// Last ditch effort: try unsuffixed.
+	rname := name;
+	if !rooted {
+		rname += "."
+	}
+	addrs, err = tryOneName(cfg, rname);
+	if err == nil {
+		cname = rname;
+		return;
+	}
 	return;
 }

src/pkg/net/net_test.go

@@ -35,7 +35,7 @@ var dialErrorTests = []DialErrorTest{
 	},
 	DialErrorTest{
 		"tcp", "", "no-such-name:80",
-		`dial tcp no-such-name:80: lookup no-such-name\..*\.( on .*)?: no (.*)`,
+		`dial tcp no-such-name:80: lookup no-such-name\.(.*\.)?( on .*)?: no (.*)`,
 	},
 	DialErrorTest{
 		"tcp", "", "mh/astro/r70:http",