Code review comment for ~sylvain-pineau/checkbox-core-snap:add-glmark2-es2

Tried to build this and run with checkbox-newparis, some errors could be found when starting glmark2-es2 in shell.

This is what I did:
1. git clone -b add-glmark2-es2 https://git.launchpad.net/~sylvain-pineau/checkbox-core-snap
2. cd checkbox-core-snap/
3. snapcraft --destructive-mode
(I'll need to install 'meson' before I started to build the snap or the build will be terminated, maybe we can add "- meson" in "build-packages" to avoid this?)
4. Copy the checkbox20_1.19.dev_amd64.snap to kmc-uno-420 hardware and side-load it with `sudo snap install checkbox20_1.19.dev_amd64.snap --devmode`
5. Connect interfaces `sudo snap connect checkbox-newparis:checkbox-runtime checkbox20:checkbox-runtime`
6. sudo checkbox-newparis.shell
7. root@CommanderBX-KSA4009233:/home/admin# glmark2-es2
Error: Failed to open models directory '/usr/share/glmark2/models'
Error: Failed to open models directory '/usr/share/glmark2/models'
Error: Failed to open models directory '/usr/share/glmark2/textures'
Error: Failed to open models directory '/usr/share/glmark2/models'
Error: Failed to open models directory '/usr/share/glmark2/models'
Error: Failed to open models directory '/usr/share/glmark2/textures'
Error: main: Could not initialize canvas