Comment 7 for bug 1756793

I'm seeing this with firefox on 18.04

```
> snap install firefox

> snap run firefox
execl failed: No such file or directory
child exited with status 1

> snap info firefox

name: firefox
summary: Mozilla Firefox web browser
publisher: mozilla
license: unknown
description: |
  The new Firefox
  Meet Firefox Quantum. Fast for good.

  Features:

    • A powerful, new engine that’s built for rapidfire performance.
    • Better, faster page loading that uses less computer memory.
    • Gorgeous design and smart features for intelligent browsing.

  Now 2x faster
  Crazy powerful browser engine? Check. Less time waiting around for pages to load? Also, check.
  Firefox Quantum is twice as fast as Firefox was before.

  Smooth browsing
  Whether you’ve opened 10 or 1000, switching between tabs is faster than ever with Firefox’s new,
  responsive engine.

  Seriously Private Browsing
  The most powerful private browsing mode with added tracking protection.

    • Private Browsing
  ◦ Firefox blocks online trackers while you browse and won’t remember your history after you’re
  done.

    • Tracking Protection
  ◦ Some ads have hidden trackers that follow you online. Rude. We know. That’s why our powerful
  tool stops them cold.

    • Faster Page Loading
  ◦ By blocking some ads and scripts that bog down browsing, pages load up to 44%!(NOVERB) faster. Now
  that’s a win-win.

  Customization Features

    • Extensions
  ◦ Customize Firefox with thousands of extensions like LastPass, uBlock Origin, Evernote and more.

    • Themes
  ◦ Make over Firefox to suit your mood! Choose a new look from our theme categories or create your
  own.

  Sync your devices
  • Seamlessly access passwords, bookmarks and more. Plus, use our Send Tabs feature to instantly
  share open tabs between desktop, mobile and tablet.

  Browse for good

  Firefox is made by Mozilla, the non-profit champions of a healthy internet. Mozilla also tackles
  issues like privacy, misinformation and trolling by investing in fellowships, campaigns and new
  technologies designed to make the internet healthier.
commands:
  - firefox
snap-id: 3wdHCAVyZEmYsCMFDE9qt92UV8rC8Wdk
tracking: stable
refreshed: 2018-03-16T10:00:17+05:30
installed: 59.0.1-1 (68) 193MB -
channels:
  stable: 59.0.1-1 (68) 193MB -
  candidate: 59.0-5 (66) 193MB -
  beta: 59.0b11-1 (57) 193MB -
  edge: 60.0b4-1 (69) 196MB -
```