Remove support for Fedora 21 (EOL); add F22 where appropriate

Fedora 21 reached its End Of Life (EOL) on 1-DEC-2015[1]; remove it as
supported distribution.

    - stack.sh: Remove Fedora 21 from list of supported distributions.
    - tools/fixup_stuff.sh: Make the minimum Fedora version to be F22 in
      from a conditional check in 'Python packages' section
    - files/rpms/general: Remove 'f21' from NOPRIME.
    - lib/ceph: Remove 'f21' from the check_os_support_ceph() function.
    - doc/source/index.rst: s/Fedora 21/Fedora 22/
    - pkg/elasticsearch.sh: Remove the 'if' conditional in the
      install_elasticsearch() function.

[1] https://fedoramagazine.org/fedora-21-end-life-december-1st/

Change-Id: Ifbcc3dd783ff2f362a464fbf4ca22f20cc2c658e
diff --git a/files/rpms/general b/files/rpms/general
index 2804682..5bc87b6 100644
--- a/files/rpms/general
+++ b/files/rpms/general
@@ -8,9 +8,9 @@
 gettext  # used for compiling message catalogs
 git-core
 graphviz # needed only for docs
-iptables-services  # NOPRIME f21,f22,f23
+iptables-services  # NOPRIME f22,f23
 java-1.7.0-openjdk-headless  # NOPRIME rhel7
-java-1.8.0-openjdk-headless  # NOPRIME f21,f22,f23
+java-1.8.0-openjdk-headless  # NOPRIME f22,f23
 libffi-devel
 libjpeg-turbo-devel # Pillow 3.0.0
 libxml2-devel # lxml
@@ -26,7 +26,7 @@
 psmisc
 pyOpenSSL # version in pip uses too much memory
 python-devel
-redhat-rpm-config # MySQL-python rhbz-1195207 f21
+redhat-rpm-config # MySQL-python rhbz-1195207
 screen
 tar
 tcpdump
diff --git a/files/rpms/nova b/files/rpms/nova
index 4db9a06..0312e85 100644
--- a/files/rpms/nova
+++ b/files/rpms/nova
@@ -7,7 +7,7 @@
 genisoimage # required for config_drive
 iptables
 iputils
-kernel-modules # dist:f21,f22,f23
+kernel-modules # dist:f22,f23
 kpartx
 kvm # NOPRIME
 libvirt-bin # NOPRIME