log/syslog: skip tests that depend on daemon on builders

Some functions in log/syslog depend on syslogd running. Instead of
treating errors caused by the daemon not running as test failures,
ignore them and skip the test.

Fixes the longtest builder.

Change-Id: I628fe4aab5f1a505edfc0748861bb976ed5917ea
Reviewed-on: https://go-review.googlesource.com/113838
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/log/syslog/syslog_test.go

@@ -214,6 +214,9 @@ func TestNew(t *testing.T) {
 
 	s, err := New(LOG_INFO|LOG_USER, "the_tag")
 	if err != nil {
+		if err.Error() == "Unix syslog delivery error" {
+			t.Skip("skipping: syslogd not running")
+		}
 		t.Fatalf("New() failed: %s", err)
 	}
 	// Don't send any messages.
@@ -226,6 +229,9 @@ func TestNewLogger(t *testing.T) {
 	}
 	f, err := NewLogger(LOG_USER|LOG_INFO, 0)
 	if f == nil {
+		if err.Error() == "Unix syslog delivery error" {
+			t.Skip("skipping: syslogd not running")
+		}
 		t.Error(err)
 	}
 }
@@ -244,6 +250,9 @@ func TestDial(t *testing.T) {
 	}
 	l, err := Dial("", "", LOG_USER|LOG_ERR, "syslog_test")
 	if err != nil {
+		if err.Error() == "Unix syslog delivery error" {
+			t.Skip("skipping: syslogd not running")
+		}
 		t.Fatalf("Dial() failed: %s", err)
 	}
 	l.Close()