With headphone plugged in, there is no sound if "Speaker" is selected

[Po-Hsu Lin]

Test case:
1. Install 16.04 + dist-upgrades
2. Plug-in a headphone, select headphone from the pop-up device selection dialog
3. Open "Sound Settings" applet, you will see two entries: Speakers and Headphone.
4. Click on "Speakers" entry as output device and try to make some noise

Expected result:
* User should see only one entry, otherwise the "Speaker" entry is expected to work when it's selected.

Actual result:
* No sound with Speaker entry (when there are two entries), but it works fine with headphones

This issue will lead to another one, bug 1583801, when user boot with headphone plugged in, as the default option will be the internal speaker, there will be no sound at all. User will need to click on the Headphone entry in Sound Settings manually, or remove and plug it back again to make headphones work (or just remove it to make internal speaker work)

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: alsa-base 1.0.25+dfsg-0ubuntu5
ProcVersionSignature: Ubuntu 4.4.0-59.80-generic 4.4.35
Uname: Linux 4.4.0-59-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/pcmC1D0c: ubuntu 1599 F...m pulseaudio
 /dev/snd/pcmC1D0p: ubuntu 1599 F...m pulseaudio
 /dev/snd/controlC1: ubuntu 1599 F.... pulseaudio
 /dev/snd/controlC0: ubuntu 1599 F.... pulseaudio
CurrentDesktop: Unity
Date: Thu Feb 2 04:16:20 2017
InstallationDate: Installed on 2017-01-16 (16 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
PackageArchitecture: all
SourcePackage: alsa-driver
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/04/2016
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A14
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: 0.1
dmi.modalias: dmi:bvnDellInc.:bvrA14:bd10/04/2016:svnDellInc.:pnInspiron7537:pvr:rvnDellInc.:rn:rvr:cvnDellInc.:ct8:cvr0.1:
dmi.product.name: Inspiron 7537
dmi.sys.vendor: Dell Inc.