Bugzilla

**Affected versions:**
    Fx 67.0b8

**Affected platforms:**
    Ubuntu 18.04

**Steps to reproduce:**
 1. Download the build from 
    https://archive.mozilla.org/pub/firefox/candidates/67.0b8- 
    candidates/build2/snap/firefox-67.0b8.snap
 2. In the directory where the .snap file is downloaded run the following 
    command snap install <name>.snap (eg. firefox-67.0b8.snap)

**Expected result:**
  - The snap  build is successfully installed.

**Actual result:**
  - The error "error: cannot find signatures with metadata for snap" appears.

**Regression range**
  - Not a regression since it also happens to 67.0b6 which was the first version 
  of snap from archive.org

**Additional notes:**
 - Using any other method to install the snap build works as intended.

**Affected versions:**
   * Fx 67.0b8

**Affected platforms:**
   * Ubuntu 18.04

**Steps to reproduce:**
 1. Download the build from 
    https://archive.mozilla.org/pub/firefox/candidates/67.0b8-candidates/build2/snap/firefox-67.0b8.snap
 2. In the directory where the .snap file is downloaded run the following 
    command snap install <name>.snap (eg. firefox-67.0b8.snap)

**Expected result:**
  * The snap  build is successfully installed.

**Actual result:**
  * The error "error: cannot find signatures with metadata for snap" appears.

**Regression range**
  * Not a regression since it also happens to 67.0b6 which was the first version 
  of snap from archive.org

**Additional notes:**
 * Using any other method to install the snap build works as intended.