Linux image 3.19.0.31 broken

Contrary to my previous message, the kernel 3.19.0.31 is completely broke.

Sound card either not found or replaced by a "Dummy device" (producing no sounds whatsoever)
Network Manager nm-applet Icon not shown in the task bar (network connection sometimes works, sometimes does not connect)

It seems that the bootup mechanism does not load all neccessary modules

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: linux-image-generic 3.19.0.31.30
ProcVersionSignature: Ubuntu 3.19.0-31.35-generic 3.19.8-ckt7
Uname: Linux 3.19.0-31-generic x86_64
NonfreeKernelModules: nvidia wl
ApportVersion: 2.17.2-0ubuntu1.5
Architecture: amd64
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/hwC1D0', '/dev/snd/pcmC1D8p', '/dev/snd/pcmC1D7p', '/dev/snd/pcmC1D3p', '/dev/snd/controlC1', '/dev/snd/by-path', '/dev/snd/hwC0D0', '/dev/snd/pcmC0D1p', '/dev/snd/pcmC0D0c', '/dev/snd/pcmC0D0p', '/dev/snd/controlC0', '/dev/snd/timer', '/dev/snd/seq'] failed with exit code 1:
Date: Wed Oct 7 21:16:31 2015
HibernationDevice: RESUME=UUID=82dd2ca4-5c1e-43dc-b83e-d93e6166e5c4
InstallationDate: Installed on 2013-05-17 (872 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64+mac (20130424)
MachineType: Apple Inc. MacBookPro10,1
ProcFB: 0 VESA VGA
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.19.0-31-generic root=UUID=3679e976-6405-4981-aa99-8c79d15e6aa3 ro quiet splash vt.handoff=7
PulseList:
 Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not accessible: Permission denied
 No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
 linux-restricted-modules-3.19.0-31-generic N/A
 linux-backports-modules-3.19.0-31-generic N/A
 linux-firmware 1.143.4
SourcePackage: linux
UpgradeStatus: Upgraded to vivid on 2015-04-25 (165 days ago)
dmi.bios.date: 12/21/2012
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBP101.88Z.00EE.B03.1212211437
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-C3EC7CD22292981F
dmi.board.vendor: Apple Inc.
dmi.board.version: MacBookPro10,1
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-C3EC7CD22292981F
dmi.modalias: dmi:bvnAppleInc.:bvrMBP101.88Z.00EE.B03.1212211437:bd12/21/2012:svnAppleInc.:pnMacBookPro10,1:pvr1.0:rvnAppleInc.:rnMac-C3EC7CD22292981F:rvrMacBookPro10,1:cvnAppleInc.:ct10:cvrMac-C3EC7CD22292981F:
dmi.product.name: MacBookPro10,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.