mime: add mime.types paths for BSDs

Change-Id: I22ac23e7e180071de4443291e0a644675200d642
Reviewed-on: https://go-review.googlesource.com/10950Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

src/mime/type_dragonfly.go

+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package mime
+
+func init() {
+	typeFiles = append(typeFiles, "/usr/local/etc/mime.types")
+}

src/mime/type_freebsd.go

+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package mime
+
+func init() {
+	typeFiles = append(typeFiles, "/usr/local/etc/mime.types")
+}

src/mime/type_openbsd.go

+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package mime
+
+func init() {
+	typeFiles = append(typeFiles, "/usr/share/misc/mime.types")
+}