Remove Fedora 19 as supported distribution

Fedora 19 will reach its end of life on 6-JAN-2015

  https://lists.fedoraproject.org/pipermail/announce/2014-December/003243.html

Remove it as a supported distribution and add Fedora 21

  - stack.sh: Remove Fedora 19 from list of 'supported' distributions.
  - tools/fixup_stuff.sh: Remove Fedora 19. Also remove the workaround
    of disabling firewalld for Fedora 21.

Change-Id: If92b87d2f9a2bb95469730cda201a7981670f727
diff --git a/stack.sh b/stack.sh
index 605d3cc..61d9cd7 100755
--- a/stack.sh
+++ b/stack.sh
@@ -143,7 +143,7 @@
 
 # Warn users who aren't on an explicitly supported distro, but allow them to
 # override check and attempt installation with ``FORCE=yes ./stack``
-if [[ ! ${DISTRO} =~ (precise|trusty|7.0|wheezy|sid|testing|jessie|f19|f20|f21|rhel6|rhel7) ]]; then
+if [[ ! ${DISTRO} =~ (precise|trusty|7.0|wheezy|sid|testing|jessie|f20|f21|rhel6|rhel7) ]]; then
     echo "WARNING: this script has not been tested on $DISTRO"
     if [[ "$FORCE" != "yes" ]]; then
         die $LINENO "If you wish to run this script anyway run with FORCE=yes"