Clean up minor warnings from LGTM.com (#7500)

* Clean up minor warnings from LGTM.com

LGTM (Semmie) is a tool, bought by GitHub last year, that conducts basic
linting tasks on code and HTML.

Clean up the warnings identified in the latest report:
https://lgtm.com/projects/g/esp8266/Arduino/?mode=list

No functionality should change, however this may fix some issues with
the perl utilities not exiting properly on a Ctrl-C from the command
line.

* Back out HTML changes and rerun boards.txt.py

libraries/ESP8266WiFi/examples/BearSSL_CertStore/certs-from-mozilla.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!/usr/bin/env python3
 
 # This script pulls the list of Mozilla trusted certificate authorities
 # from the web at the "mozurl" below, parses the file to grab the PEM
@@ -14,11 +14,11 @@ import sys
 from subprocess import Popen, PIPE, call
 try:
     from urllib.request import urlopen
-except:
+except Exception:
     from urllib2 import urlopen
 try:
     from StringIO import StringIO
-except:
+except Exception:
     from io import StringIO
 
 # Mozilla's URL for the CSV file with included PEM certs
@@ -42,7 +42,7 @@ del pems[0] # Remove headers
 # Try and make ./data, skip if present
 try:
     os.mkdir("data")
-except:
+except Exception:
     pass
 
 derFiles = []