Prepare for the 0.33.1 release. (#6915)

The changelog should still say <version> - master because it will be fixed up automatically by the release script at https://github.com/certbot/certbot/blob/master/tools/_release.sh#L69.

* Protect certbot-auto against non numerical version release in some RPM distributions (#6913)

Fixes #6912

Bash evaluate all condition in a predicate statement, eg. `"$SOMEVAR" = "test" -a "$ANOTHERVAR" = "test2"`, even if it is not necessary, for instance if the first condition is false in the example here.

As a consequence, on non-Fedora distributions, an evaluation of the distribution version could be done on non numeric value, eg. `"6.7" -eq "29"`, making certbot-auto failing in this case.

This PR fixes that, by evaluating the version on RPM distributions only if we are on Fedora. Otherwise, version will be "0".

(cherry picked from commit c2d9ea1f61)

* Update changelog about #6912 fix. (#6914)

(cherry picked from commit 30eafba997)

* cleanup changelog

letsencrypt-auto-source/letsencrypt-auto

@@ -750,7 +750,10 @@ elif [ -f /etc/redhat-release ]; then
   DeterminePythonVersion "NOCRASH"
   # Starting to Fedora 29, python2 is on a deprecation path. Let's move to python3 then.
   RPM_DIST_NAME=`(. /etc/os-release 2> /dev/null && echo $ID) || echo "unknown"`
-  RPM_DIST_VERSION=`(. /etc/os-release 2> /dev/null && echo $VERSION_ID) || echo "0"`
+  RPM_DIST_VERSION=0
+  if [ "$RPM_DIST_NAME" = "fedora" ]; then
+    RPM_DIST_VERSION=`(. /etc/os-release 2> /dev/null && echo $VERSION_ID) || echo "0"`
+  fi
   if [ "$RPM_DIST_NAME" = "fedora" -a "$RPM_DIST_VERSION" -ge 29 -o "$PYVER" -eq 26 ]; then
     Bootstrap() {
       BootstrapMessage "RedHat-based OSes that will use Python3"