Install python3-openssl if not already installed.

tests/test_ssl.py

@@ -7,12 +7,18 @@ Checks that TLS certificates are valid; if invalid, the user will have to add an
 '''
 import datetime
 import imp
-import OpenSSL
 import os
 import requests
 import sys
 import ssl
 
+try:
+    import OpenSSL
+except ImportError:
+    import subprocess
+    subprocess.call(['apt-get', '-qq', '-y', 'install', 'python3-openssl'])
+    import OpenSSL
+
 YELLOW = '\033[93m'
 GREEN = '\033[92m'
 RED = '\033[91m'