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