Merge v1.2.1-master

Signed-off-by: Emile Vauge <emile@vauge.com>

vendor/github.com/Sirupsen/logrus/terminal_solaris.go

@@ -1,15 +1,21 @@
-// +build solaris
+// +build solaris,!appengine
 
 package logrus
 
 import (
+	"io"
 	"os"
 
 	"golang.org/x/sys/unix"
 )
 
 // IsTerminal returns true if the given file descriptor is a terminal.
-func IsTerminal() bool {
-	_, err := unix.IoctlGetTermios(int(os.Stdout.Fd()), unix.TCGETA)
-	return err == nil
+func IsTerminal(f io.Writer) bool {
+	switch v := f.(type) {
+	case *os.File:
+		_, err := unix.IoctlGetTermios(int(v.Fd()), unix.TCGETA)
+		return err == nil
+	default:
+		return false
+	}
 }