XDG_DATA_DIRS has directories with trailing slashes

[Kaleb Hornsby]

The file `/etc/X11/Xsession.d/60x11-common_xdg_path` sets DEFAULT_XDG_DATA_DIRS='/usr/local/share/:/usr/share/' incorrectly by adding trailing slashes to its two elements.

This is the output of XDG_DATA_DIRS: /usr/share/ubuntu:/usr/share/gnome:/usr/local/share/:/usr/share/:/var/lib/snapd/desktop

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: x11-common 1:7.7+13ubuntu3
ProcVersionSignature: Ubuntu 4.4.0-28.47-generic 4.4.13
Uname: Linux 4.4.0-28-generic x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Sat Jul 9 14:45:43 2016
Dependencies: lsb-base 9.20160110
DistUpgraded: 2016-04-22 19:53:21,414 DEBUG icon theme changed, re-reading
DistroCodename: xenial
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, including running git bisection searches
GraphicsCard:
 Intel Corporation Haswell-ULT Integrated Graphics Controller [8086:0a16] (rev 0b) (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. Haswell-ULT Integrated Graphics Controller [1043:168d]
InstallationDate: Installed on 2015-10-30 (253 days ago)
InstallationMedia: Ubuntu 14.10 "Utopic Unicorn" - Release amd64 (20141022.1)
MachineType: ASUSTeK COMPUTER INC. Q502LA
PackageArchitecture: all
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-28-generic.efi.signed root=UUID=efe516cf-31f8-4db3-b924-fceaee6d82ce ro quiet splash vt.handoff=7
SourcePackage: xorg
UpgradeStatus: Upgraded to xenial on 2016-04-22 (77 days ago)
dmi.bios.date: 06/03/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: Q502LA.204
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: Q502LA
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrQ502LA.204:bd06/03/2014:svnASUSTeKCOMPUTERINC.:pnQ502LA:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnQ502LA:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:
dmi.product.name: Q502LA
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.
version.compiz: compiz 1:0.9.12.2+16.04.20160526-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.67-1ubuntu0.16.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 11.2.0-1ubuntu2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.2.0-1ubuntu2
version.xserver-xorg-core: xserver-xorg-core 2:1.18.3-1ubuntu2.2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Fri Jul 8 12:17:53 2016
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:
 product id 1111
 vendor LGD
xserver.version: 2:1.18.3-1ubuntu2.2